KR101486404B1 - Powder-containing oil-based lubricating agent for mold, electrostatic coating method using the powder-containing oil-based lubricating agent, and electrostatic coating apparatus - Google Patents

Abstract

An oil-based lubricant which is applied to a mold used for high-pressure casting, gravity casting, low-pressure casting and forging, and which can prevent press-adhesion under a high temperature region and a high load, an application method for applying the oil- And to provide the above-mentioned objects.
The mold-containing oil lubricant for mold comprises 60% by mass to 99% by mass of an oily lubricant composed of oil, 0.3% by mass to 30% by mass of solubilizing agent, 0.3% by mass to 15% by mass of inorganic powder and 7.5% Is electrostatically applied. Further, in the electrostatic application method, the aforementioned oil-based lubricant containing powder for a mold is electrostatically coated on a metal mold. Furthermore, the electrostatic coating apparatus further includes an electrostatic imparting device for applying electrostatic force to the lubricant containing the metal powder and an electrostatic coating gun provided on the multi-axis robot.

Description

TECHNICAL FIELD [0001] The present invention relates to a powder-containing oil-based lubricant for a metal mold, an electrostatic coating method using the same, and an electrostatic coating device using the same. BACKGROUND ART < RTI ID = 0.0 >

TECHNICAL FIELD The present invention relates to a powder-containing oily lubricant used in a mold for casting and forging a non-ferrous metal such as aluminum, magnesium and zinc, an electrostatic application method using the lubricant, and an electrostatic application device.

As is known, there are methods such as casting, forging, press working, and extrusion processing for the steps of using a metal mold in the processing of a non-ferrous metal. In the process, casting is largely classified into high-pressure casting, gravity casting, low-pressure casting, and squeeze casting. Forging is largely classified into cold forging and hot forging. In terms of the material to be processed, it is largely classified into iron, non-ferrous metals and plastics. The lubricant applied to the mold surface is largely classified into a water-soluble lubricant and an oil-based lubricant, and the water-soluble lubricant is classified into a transparent solution type and an opaque emulsified type in a milk-like state. From the viewpoint of the components in the lubricant, it can be classified into a type containing a powder and a type not containing a powder. In the application method, brush application, droplet drop, and spray are largely distinguished. The spray can be classified into the advection method and the first-flow method, and the combination of the non-invasive type and the static type.

The basic processes of high pressure casting, gravity casting and low pressure casting are the same. These processes are likened to the process of applying oil to a frying pan and pouring a mixed egg-seed mixture thereon to make an egg drop. When casting nonferrous metal, apply lubricant (corresponding to edible oil) to mold to prevent sticking of mold (corresponding to frying pan) and molten metal Thereafter, the molten high-temperature molten metal is poured into the mold, and after the solidification, the product (corresponding to the egg stick) is taken out. However, in terms of the production efficiency and the strength quality of the cast product, the high-pressure casting achieves a low-strength product at a high production efficiency, the gravity casting obtains a high-strength product at a low production efficiency, With the production efficiency of the gravity casting side, the strength of the gravity casting side is obtained. It is necessary to produce high-strength products even if they are low in production efficiency, as far as they are likely to be related to the risk of human life caused by the destruction of parts. In the production of parts that are not related to human life even if they are destroyed, production efficiency is emphasized even if the air is slightly blown into the sponge and the strength is lowered. That is, the main difference between these methods is the difference in the filling speed of the molten metal in the mold part, and the speed is accelerated in the order of gravity casting, low-pressure casting and high-pressure casting. Therefore, the amount of heat received by the coating film formed on the mold is different, and the most heat is received in the gravity casting, and the most heat received in the high-pressure casting is small. Depending on the amount of heat, the lubricant may be decomposed or lost, and other lubrication techniques are currently being used.

On the other hand, in the forging process, it is likened to the production of a knife and is a method of increasing the strength by tapping the solidified metal. It is also a method of deforming a solidified metal into a desired shape by tapping with a high pressure. The time for which the coating film is exposed to high temperature is short, but it is exposed to very high pressure. Therefore, it is the present situation that the lubrication technique which is considerably different from the casting is used.

With respect to the combination of these various types, it is difficult to satisfy all requirements with one kind of lubricant, and it is a present situation that individual lubrication techniques are utilized for each use. However, a lubrication technique in which two or three combinations are considered is possible. The present application relates to a lubrication technique aiming at the integration of these plural kinds of technologies and will be described in the order of high-pressure casting, gravity and low-pressure casting, and forging in this order.

A) High pressure casting

Over the past 40 years, more than 90% of non-ferrous metal lubricants and release agents such as aluminum, magnesium, and zinc are accepting mold release agents. The water-soluble releasing agent in which the active ingredient is emulsified in water is applied to the mold by an air-spraying method using mainly air pressure. Electrostatic spraying technology can not be utilized at all for water-soluble releasing agents which are excessively conductive.

Oil-based lubricants, which enable casting with a small amount of coating of 1/500 to 1/1000 compared to the amount of water-soluble use, have started to be used many years ago. However, since only a very small amount of the oil lubricant can be applied, formation of a coating film may be insufficient in a metal mold having a complicated structure or a large metal mold. In the case of a mold having a complicated structure, formation of a coating film at a metal mold portion hidden from the coated surface tends to be insufficient. In addition, since the mold has irregularities, a coating film is formed thickly in the concave portion, but a thin coating film tends to be formed in the convex portion. For this reason, in the concave portion, an oily lubricant component is excessively added, which causes pores (sponge formation) of the cast product to increase. In the convex portion, the mold and the cast product are liable to cause adhesion and sticking due to lack of lubricity. As a countermeasure at the production site, it is a current situation that the application amount of the oily lubricant is increased so as to reach a lot of splash particles sprayed on the hidden part and the convex part while sacrificing a slight increase of the porosity. Further, in the case of a large mold, the heat energy of the molten metal of the non-ferrous metal is large. Therefore, the temperature of the entire mold, especially in the narrow region, is close to the temperature of the molten metal, resulting in a high temperature of 350 DEG C or higher. For this reason, the oily lubricant causes a phenomenon called Leidenfrost, and the droplet of the oily lubricant boils. As a result, the wettability of the oily lubricant to the mold surface is deteriorated. That is, the droplet scattering from the mold surface to the bottom increases due to boiling. As a result, the coating film to be formed becomes thin, and the lubricity may be poor.

A countermeasure in the case of a water-soluble release agent is to apply a large amount of the solution to cool the mold and adhere at a temperature lower than the Leiden frost temperature. Of course, problems arise due to drainage. As a countermeasure in the case of the oily lubricant, two methods are taken. One is to apply the coating in a generous manner in order to thicken the coating film. The other is to apply a small amount of water to almost evaporate to cool the narrow high-temperature region, and then apply an oily lubricant. When the oil lubricant is applied in a satisfactory manner, the thickness of the coating film at the portion where a sufficient coating film is formed also increases. As a result, the amount of pores in the cast product tends to increase. In addition, the strength of the cast product may be slightly lowered. In addition, even a small amount of water requires piping for application.

That is, the prior art has the following problems.

1) Since the oil lubricant is not sufficiently supplied to the hidden part of the mold, it is difficult to form a coating film necessary for lubrication at that part.

2) It is difficult to form a coating film of sufficient thickness in a narrow part of the mold.

3) It is difficult to form a uniform coating film at the concave and convex portions of the mold.

In order to solve the problems of these oily lubricants, electrostatic application is an effective means. The oily lubricant oil droplets are negatively charged by the application device and sprayed onto the positive charge mold. It is a technique that allows the sprayed lubricant residue to reach the hidden part of the mold. However, since the water-soluble release agent is excessively good in electric conductivity, electrostatic application can not be applied. Patent Document 1 relates to a technique of lowering the electric resistance value by adding alcohol or ammonium salt as an electrostatic additive as a means for imparting conductivity to a coating material. However, alcohol or ammonium mist is not desirable at the casting site. Patent Document 2 relates to a technique in which an electrostatic coating agent is added to a coating material. However, the " electrostatic precipitator having a strong polarity " is dissolved only in about 0.3% by mass in the " low-polarity oil-based lubricant " As a result of examination by the present applicants, at this level, the effect of increasing the deposition amount of the electrostatic agent was not observed. Addition of polar solvents increases the dissolution of electrostatic agents, but polar solvents tend to harm the health of field workers. Therefore, a solvent having a polarity from the consideration of health is not preferable for the composition of the oily lubricant.

In order to solve the additional problems associated with the electrostatic application as described above, the present applicants have proposed a technique of electrostatically applying a small amount of conductivity imparting water and a solubilizing agent to an oil-based lubricant to apply it to a mold for high-pressure casting . However, there is a tendency that it is difficult to cope with pressing due to the high temperature of the lubricating surface caused by a lack of cooling property caused by a small amount of application of the lubricant.

B) Gravity and low pressure casting

In the cast lubricant coating film, the flow rate of the molten metal at casting is a large factor. If the flow rate of the molten metal is extremely low as in the case of gravity casting, the time in which the lubricating coating film is in contact with the molten metal at a high temperature of about 600 DEG C is prolonged, and the lubricating coating film is remarkably deteriorated. As a result, when the coated film becomes thinner and the molten metal solidifies, it may be adhered to the mold. For this reason, it is a current situation that a " coating agent " in which an inorganic powder is dissolved in water is mainly used so as not to be affected by deterioration. The coating film made of graphite is a powder and does not deteriorate. However, since the mold-making agent contains water, drying is required. For example, it corresponds to the process of plastering used in Japanese houses and requires drying for a long time. In the case of casting, if molten metal is introduced before drying, the molten aluminum and water will cause water vapor explosion. Therefore, the drying process for several hours after application is indispensable, and the production efficiency is extremely lowered when "coating, drying, and producing every casting". Therefore, in order to omit the drying process, it is a current situation that " apply once every several tens or hundreds of production. &Quot; It is said that the application of the patterning agent is only a skill of a skilled craftsmanship, and a good craftsmanship can produce more than 100 pieces per application. Some craftsmen with poor craftsmanship can not even produce ten. In addition, the thick coating film made of graphite may be partially peeled off. The exfoliated powder is mixed into the product and the strength of the product is extremely reduced. Since it is unclear when peeling occurs, the entire cast product of the lot which caused peeling is generally rejected and recovered. In addition, if the coating film is peeled from the product surface, the peeled product part becomes convex, resulting in poor appearance.

In the casting process, it is important not only to prevent sticking but also to completely melt the portion of the mold which is finely engraved, and to finish the product in the expected form. In order to secure such a flow of hot water, a thick coating agent is applied. That is, the cooling of the molten metal is delayed, the viscosity of the molten metal is kept low, and the molten metal is uniformly distributed in the fine portion of the metal mold. As described above, a thick coating film (thickness of several tens to hundreds of tens of micrometers) is secured by coating once every several tens of times, but a small amount of powder is mixed in the product per casting. As a result, the coated film gradually becomes thinner, and the heat insulating efficiency is lowered. Finally, the molten metal temperature is lowered, the molten metal flow can not be ensured, and the molten metal does not flow to every corner of the metal mold. In other words, the broken egg shape is completed. The initial coating film is thick and the coating film after casting several tens times is thin. Therefore, a difference occurs between the cooling rate of the initial product and the cooling rate after casting several tens of times. As a result, the crystal structure of the metal is different, and the quality of the product is different at the initial stage of application and after the application. In other words, frequent application is required to stabilize the quality of the product, but since frequent drying after application is also required, the production efficiency is lowered. It is applied at a small thickness at an early stage while sacrificing stable quality and thinner to deteriorate lubricity, thereby reducing inefficient drying processes.

In addition, a product made of a coated film generally has a polished surface, but some products do not satisfy the apparent quality requirement, and therefore post-treatment for emitting light is required. In addition, since 100% of the powder is used except for water, scattering of the powder after drying can not be avoided, and working environment is also required.

As techniques for compensating for such drawbacks, the techniques described in Patent Document 3 and Patent Document 4 are known. Both technologies relate to oily lubricants that do not contain water in order to drastically reduce drying time. In addition, by increasing the number of times of application, an excessively thick coating is avoided to produce a coating film that is more homogeneous than the conventional coating agent. Further, by reducing the content of the powder, the film is made as thin as possible to prevent peeling of the film. Also, since it is a low-concentration powder, scattering of powder at the production site is suppressed as much as possible.

C) Forging

Forging is a method of compressing and deforming a metal material to be produced. This method can be divided into two types, free forging and die forging. Without a mold, a knife knocking a steel is a good example of free forging. On the other hand, molds are used for homogenization of products by using molds. The crankshaft of the engine component is a good example of mold forging. Further, in order to reduce the compressive force required for deformation, the material to be cut (hereinafter, referred to as a work) is heated and softened. Depending on the material of the workpiece, the heating temperature differs. Generally, it is classified into cold forging, warm forging, and hot forging depending on degree of heating, but there is no definite classification by quantification.

The cold forging is carried out at a temperature not higher than the recrystallization temperature of the work (usually at room temperature), and the dimensional precision is very high. Therefore, in many cases, commercialization is possible without post-processing. Cold forging is suitable for small products. On the other hand, hot forging is performed at a temperature higher than the recrystallization temperature and is applied to a large product. However, an oxide film is formed on the surface of the work, and cracking of the product is likely to occur. Further, since the metal is deformed, the work is compressed at a high pressure. When there is no lubricant between the workpiece and the mold, it causes scratches or adhesion between the workpiece and the mold. Therefore, a lubricant is applied to the mold for the purpose of preventing scratching and adhesion.

Generally, in cold forging, it is easy to form a coating film by physical adsorption. On the other hand, at a high temperature of hot forging, a lubricant frost phenomenon occurs at a high temperature, and the lubricant component is hardly attached to the mold. Further, even when adhered, the physical adsorption force is weak, and formation of a coating film becomes difficult. In the case of a lubricant using water as a medium, water can not be dried at 100 DEG C or lower, so that lubrication can not be performed, but a coating film is easily formed at an intermediate temperature. However, when the temperature exceeds 240 캜, it is difficult to form a coating film due to the phenomenon of layden frost.

As a material for forming a coating film in the market, the following form can be mentioned.

1) Graphite: Two types of lubricants: oil-in-water (water-emulsified) and oil-dispersed.

2) White powder system: Liquid form of mica, boron nitride, or melamine cyanurate.

3) Glass system: A mixed system of an alkali metal salt of a colloidal silicic acid and an aromatic carboxylic acid (Patent Document 5), which is diluted with water and used.

4) Water-soluble polymer system: Containing water (Patent Document 6).

Graphite exhibits excellent lubricity from low temperature to high temperature. However, in the case of graphite, the working environment is poor due to being dirty with black powder. Particularly, a lubricant of a type in which graphite is blended with oil causes remarkable dirt. The lubricant, which is mainly white powder, does not deteriorate the working environment as much as graphite, but if the powder content is high, the work site is defiled. Further, the white powder is inferior in lubricity to graphite. Further, the white powder may have high hardness, which may damage the surface of the mold and shorten the life of the mold.

Glass-based and polymer-based lubricants can form thick coatings, but are less lubricous than graphite and have a short mold life. Further, the glass-based lubricant forms a glass film or a polymer film around the device, and is not as good as a white powder, but requires periodic cleaning work, resulting in poor working efficiency.

Since graphite and white powder lubricants are dispersed in water or oil, there is always a problem of separation during storage and clogging of piping and spray. In the water-glass type, drying takes place near the nozzle to be coated. In particular, if the operation is interrupted for a long time, the drying is promoted and clogging of the nozzle tip occurs. As a result, when the work is resumed, the application amount decreases. Therefore, since the lubricating ability is insufficient, defective products are generated. The lubricating agent of the feeding system is good in the coolability of the mold, but it is necessary to treat wastewater.

When the mold surface exceeds 230 DEG C, the mist of the lubricant surrounded by the water boils on the mold surface. As a result, the efficiency of attaching the lubricant to the mold becomes poor, and it becomes necessary to apply a large amount of the lubricant. That is, since the formation of the coating film of the water-soluble lubricant is highly dependent on the temperature, strict control of the mold temperature is indispensable. Since water is difficult to evaporate below 100 ° C, emulsified lubricants are not suitable for cold forging. On the other hand, the emulsifying type lubricant can be used for warm and hot forging. However, water cools the mold and the work heats the mold. When this heating and cooling cycle is repeated, a crack is generated in the mold. The repair of the mold becomes necessary and, in addition, when the number of repairs increases, it reaches the disposal of the expensive mold. That is, water shortens the life of the mold. In addition, when the work temperature is remarkably lowered in the molding step, molding under high load becomes necessary, which is a factor of shortening the life of the mold.

With respect to the application method of the lubricant, there is a problem that the cycle time (working time for producing one product) increases when a large amount is applied. In the case of a water-soluble lubricant, since it is applied in a large amount, it is not preferable from the viewpoint of production efficiency. Further, due to scattering of the lubricant by mass application, problems such as deterioration of the working environment and increase in the frequency of lubricant replenishment can be considered. In addition, the heating process of the workpiece may cause a decrease in productivity. The production process using a conventional water-soluble lubricant varies after the temperature rise of the work, and there are processes such as preliminary molding, rough molding and finish molding. At that time, since the molding process proceeds and the temperature of the work is lowered, the deformation resistance increases and molding becomes difficult. Particularly, in the case of the water-soluble lubricant, since the coating amount is large, the mold is cooled and the temperature drop is accelerated. As a countermeasure therefor, there is a case where a re-win-on process is added. However, the re-start-up process causes a decrease in production efficiency such as a cycle time, a space, an operation cost, and the like.

In order to solve the above problems, the present applicants have proposed a lubricant containing a low concentration of powder. Because it is oil-based, it does not contain water, and thus it is possible to prevent deterioration of productivity caused by water and deterioration of production cost. In addition, the powder amount is low, and it is possible to reduce deterioration of the on-site environment and to reduce the problem of settling at the time of lubricant storage. In addition, since a small amount of coating is applied, the reheating process can be reduced because the cooling capacity is small, and the production efficiency is good. However, under high load, scratches occur depending on the conditions.

In each case, although the conventional technique has been established to a certain extent, no technique relating to a lubricant that can be commonly used in high-pressure casting, gravity and low-pressure casting and forging can be found.

Patent Document 1: Japanese Patent Application Laid-Open No. 9-235496 Patent Document 2: Japanese Patent Application Laid-Open No. 2000-153217 Patent Document 3: Japanese Patent Application Laid-Open No. 2007-253204 Patent Document 4: Japanese Patent Application Laid-Open No. 2008-93722 Patent Document 5: Japanese Patent Application Laid-Open No. 60-1293 Patent Document 6: JP-A-1-299895

The present invention relates to a composition for preventing " electrostatic coating " of an " oily lubricant " containing " powder " in a mold of high pressure casting, gravity casting, low pressure casting and forging, , A coating method for applying the composition, and a coating apparatus for coating.

The first invention is characterized by comprising 60% by mass to 99% by mass of an oily lubricant composed of oil, 0.3% by mass to 30% by mass of a solubilizing agent, 0.3% by mass to 15% by mass of an inorganic powder and 7.5% Wherein the lubricating oil composition contains 60 to 98.7% by mass of an oil-based lubricant comprising an oil, 0.8 to 30% by mass of a solubilizer, 0.3 to 15% by mass and 0.2% by mass of an inorganic powder, To 7.5% by mass, and electrostatically applied to the mold.

The second invention relates to an electrostatic application method for electrostatically applying the above-mentioned oil-based lubricant containing a metal powder onto a metal mold.

The third invention is a method for manufacturing an electrostatic latent electrostatic latent image bearing member, comprising an electrostatic imparting device for applying electrostatic force to the lubricant containing the mold powder and an electrostatic application gun provided on the multi-axis robot, ≪ / RTI >

INDUSTRIAL APPLICABILITY According to the present invention, when electrostatically applied to a metal mold of high-pressure casting, gravity casting, low-pressure casting or forging, it is possible to prevent the pressurized and adhered portions from being hidden under high-

Fig. 1 (A) is an explanatory diagram of a schematic overall view of the electrostatic coating device of the present invention. Fig. 1 (B) is a view for explaining a state in which a lubricant is applied to a mold from an electrostatic coating gun, which is a part of the electrostatic coating apparatus in Fig. 1 (A).
Fig. 2 is an explanatory diagram of a laboratory-type adhesion amount measurement tester simulating attachment of an oily lubricant in an actual mold.
3 is an explanatory diagram of a laboratory type friction tester for estimating a friction force required when taking out a solidified aluminum product from an actual mold. Fig. 3 (A) illustrates a situation in which a lubricant is applied to the test piece. Fig. 3 (B) illustrates a situation in which molten aluminum is solidified on a test piece coated with a lubricant, and then friction force is measured.
Fig. 4 shows the arrangement for installing the test piece in parallel with the application direction in confirming the electrostatic application effect.
Fig. 5 is an overall view of a bath flow tester for measuring the length of the molten aluminum melted at high temperature until it solidifies.
Fig. 6 is a view showing a side surface of a stage constituting the flow tester of Fig. 5. Fig.
7 is a view showing a lid constituting the bath flowability tester of Fig. Fig. 7 (A) shows the side face of the lid, and Fig. 7 (B) shows the back face of the lid.
Fig. 8 is a view showing a measure and a bar used in the flow-flow test by the flow-flow tester of Fig. Fig. 8 (A) is a diagram for use in the flow flow test, and Fig. 8 (B) is a diagram showing the bars used in the flow flow test.
Fig. 9 is a schematic view of a moldability evaluation tester simulating an actual gravity casting apparatus.
10 is a detailed view of a left mold constituting the moldability evaluation tester of Fig.
11 is a detailed view of a right mold constituting the moldability evaluation tester of Fig.
12 is a diagram for explaining the operation of the formability evaluation test.
13 is a view showing a cast product solidified by the formability evaluation test.
14 is a diagram for explaining the outline of a ring compression tester simulating actual forging.
15 is an explanatory diagram of a situation in which an electrostatic coating apparatus is mounted on an actual forging apparatus in a tentative manner.

Hereinafter, the first invention will be described in more detail.

a) Oily lubricant

The oily lubricant used in the first invention refers to a flammable substance which is composed of oil and does not mix with water without a surfactant or a later-described solubilizing agent, has a low polarity, and is liquid at room temperature. Oily lubricants include oil-based saturated hydrocarbon components (solvent or mineral oils and synthetic oils) and lubricity enhancing agents (lubricants such as silicone oils, animal and vegetable oils and fatty acid esters) that enhance lubricity and high viscosity oils Based hydrocarbon oil component. For example, those described in International Publication No. WO2006 / 025368 include lubricants and releasing agents conventionally called " startup agents ".

The oil-based lubricant is 60% by mass to 99% by mass of the powdery lubricous lubricant of the present invention. Further, it is preferably 60 mass% to 98.7 mass%, more preferably 70 mass% to 90 mass%. If it is less than 60% by mass, dryness on the mold surface becomes poor, and if it exceeds 99% by mass, the coating film on the mold surface becomes thin, and the lubricity tends to decrease.

As the petroleum-based saturated hydrocarbon component, it is preferable to mainly use a solvent or a mineral oil or a synthetic oil. These components are a mixture of several tens to several thousand compounds. When the boiling point is low, they are called a solvent, while when they have a high boiling point, they are called mineral oil or synthetic oil, but there is no definite distinction. Usually, it is divided into a flash point which is an indicator of volatility rather than a boiling point. Very generally, a solvent is considered to have a flash point of about 150 ° C or less, and a mineral oil or synthetic oil of more than 200 ° C, and the intermediate component is sometimes called a solvent, sometimes mineral oil. If the flash point of the oil-based lubricant is low, a firm coating film is formed with good dryability, however, the risk of ignition increases and the film thickness becomes thin. On the other hand, if the ignition point of the oily lubricant is high, the risk of ignition is reduced, but the drying property is lowered and the coating film becomes apparently thicker, but the excess portion is increased and separated by heat. As a result, there is a tendency to cause pores. Among the powder-containing lubricant of the present invention, the petroleum-based saturated hydrocarbon is preferably in a range of 70 ° C to 250 ° C as the flash point. Further, the above-mentioned highly viscous petroleum hydrocarbon acts as a binder for holding a coating film, and it is preferable that it has a flash point (low volatility) of 250 deg. If the flash point is lower than 70 캜, it is classified as a second petroleum with a high risk of fire.

As the solvent of the petroleum-based saturated hydrocarbon component, a hydrocarbon which is a liquid at a room temperature of 10 or more carbon atoms may be mentioned. Specific examples thereof include decane, dodecane, octadecane, and petroleum solvents having 15 carbon atoms. Among them, petroleum hydrocarbons having 14 to 16 carbon atoms are preferable from the viewpoint of fire risk and drying property on the mold surface. Examples of the petroleum-based saturated hydrocarbon-based mineral oil include spindle oil, machine oil, motor oil, and cylinder oil. Examples of the synthetic oil of the petroleum-based saturated hydrocarbon component include polyalphaolefins (such as ethylene-propylene copolymer, polybutene, 1-octene oligomer, 1-decene oligomer and hydrides thereof), monoesters Di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), poly (Trimethylolpropane) propylate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelanate and the like), polyoxyalkylene glycol, polyoxyethylene glycol, Polyphenyl ether, dialkyl diphenyl ether, phosphoric acid ester (tricresyl phosphate and the like).

Examples of the lubricity improver component include fatty acids, organic acids, alcohols, and silicones. Examples of the fatty acid component include vegetable oils such as rape seed oil, soybean oil, palm oil, and palm oil. Examples of organic acids include oleic acid, stearic acid, palmitic acid and lauric acid, and monohydric alcohol esters of higher fatty acids such as tallow fatty acid. Examples of alcohols include polyhydric alcohol esters. Examples of the silicone oil component include dimethyl silicone and alkyl-modified silicone. Among them, rapeseed oil and alkyl-modified silicone are preferable from the viewpoint of lubricity at high temperature. As the oil-based lubricant, any one of them may be used alone, or two or more of them may be used in combination.

b) Solubilizing agent

In the present invention, the solubilizing agent is a substance which dissolves water and dissolves in an oil-based lubricant having a low polarity, and includes an alcohol, a glycol, an ester, an ether, a ketone solvent, or an emulsifier. If these solvents in which water is dissolved are also insoluble in the oily lubricant, water and a part of the solvent may be separated from each other and turbidity may be generated. As a result, the electric resistance becomes infinite. Lower alcohols and glycols of C1 and C2 tend to dissolve in water, but tend to cause separation in petroleum-based oil-based lubricants. In addition, since the oily lubricant is used while being applied, it is required to have a low toxicity and a low polarity solvent with less influence on the health of workers. Properties close to odor are also important. In view of these points, in order to dissolve water in an oil-based lubricant having a low polarity, a nonionic or anionic compound having hydrophilic and hydrophobic groups, which is easier to vaporize than a lower alcohol such as ether or ketone, Type emulsifier is most preferable as a solubilizing agent.

From the viewpoint of solubilization ability, a solubilizing agent having a Hydrophile-Lipophile Balance (HLB) of 5 to 10 is most preferred. If the HLB is less than 5, it is difficult to dissolve the water, but it is easy to melt in the oil. Therefore, in order to dissolve a certain amount of water in the oily lubricant, a large amount of solubilizing agent is required. If the HLB is more than 10, it is easy to dissolve water, but it is difficult to dissolve in oil. Therefore, if a certain amount of water is dissolved in the oily lubricant, separation occurs. As a suitable solubilizing agent, it is most preferable to have an appropriate HLB range. As the emulsifier, a non-ionic type sorbitan system free from such problems is preferable to a phenol-ether type having a problem as an environmental hormone.

Mixing of the solubilizing agent may inhibit the inherent lubricity of the oily lubricant and increase the generation of pores in the cast aluminum product. In order to minimize these problems, it is important to suppress the amount of the solubilizing agent to be low. The amount of the solubilizing agent is preferably 9 times or less the water content. The solubilizing agent is 0.3% by mass to 30% by mass in the powdery oil-based lubricant of the present invention. When the amount is less than 0.3 mass%, the solubilizer can not dissolve the water and causes the problem that the water is separated from the other components. When the solubilizer exceeds 30 mass%, the solubilizer itself tends to be separated from other components. Further, it is preferably 0.8% by mass to 30% by mass.

c) Inorganic powder

Each component of the oily lubricant, water, and solubilizer described above is decomposed in several seconds in a temperature range exceeding 400 캜. Some of them have a component that maintains lubricity even when decomposed, but the coated film becomes thinner and the heat insulating property is lowered. When the coating film is thinned, the metal mold and the metal melt are brought into direct contact with each other, so that they can be caught and adhered to each other. Further, when the heat insulating property is lowered, the temperature of the molten metal is lowered, and the viscosity of the molten metal is increased. As a result, the molten aluminum does not flow to every corner of the mold, making it impossible to cast a desired shape product. On the other hand, in the case of forging, if the heat insulating property is lowered, the temperature of the work is lowered and hardened. As a result, in order to deform the work, a larger force is required. As described later in Examples, it has been confirmed that the inorganic powder is hard to deteriorate at a high temperature, maintains a thick coating film, and exerts heat insulation property. In other words, the inorganic powder is effective for prevention of sticking in casting, prevention of sticking in forging, and reduction of work strain pressure.

Examples of inorganic powders include talc, mica, mica, clay, silica, refractory mortar, boronite, fluorine resin, sericite, borate, alumina powder, pyrophosphate, bicarbonate, titanium oxide, , Zirconium oxide, graphite, carbon black, and the like. Among them, clay in which an organic matter is adsorbed on the surface of the powder is most preferable in order to give a sedimentation preventing property of the powder in oil. In addition, calcium carbonate is preferred because it has a relatively low specific gravity and is relatively difficult to precipitate. The blending amount of the inorganic powder is preferably from 0.3% by mass to 15% by mass, and more preferably from 1% by mass to 10% by mass. If it is more than 15% by mass, storage for a long period of time after production causes a problem that the inorganic powder precipitates before using the oil-based lubricant, and furthermore, the cast product and the work are scratched and the gloss of the surface is deteriorated. Also, the work site becomes dirty with powder. On the other hand, when the content is less than 0.3% by mass, the effect of preventing adhesion at high temperatures is reduced.

d) Water

The oily lubricant described in a) has an infinite electric resistance value and is not suitable for electrostatic application. However, by adjusting the electric resistance value of the oily lubricant within the range of 5 MΩ to 400 MΩ, electrostatic application becomes possible. For example, when 0.8 wt% of water is dissolved in the oily lubricant with the help of a solubilizing agent, the electric resistance value drops to about 20 M OMEGA. The detailed test results will be described later, but water is added in an amount of 0% by mass to 7.5% by mass in the powdery oily lubricant of the present invention. Further, it is more preferable to add 0.2 to 7.5% by mass of water. When the amount of water exceeds 7.5% by mass, separation of water from the oily lubricant occurs, and the lubricant in storage is altered. On the other hand, even in the case where the water content is 0 mass%, the resistance of the ohmmeter measured at a low voltage of 1.5 V shows infinity, but a component having a polarity such as a lubricity improving agent undergoes a slight electrostatic charge Effect. In Table 2 to be described later, when the water is mixed at 0.1 mass%, the electric resistance decreases from infinity to 1500 MΩ, and when 0.4 mass% is mixed, the electric resistance decreases at 900 MΩ. If the water is less than 0.2 mass% The degree of decrease in the resistance value tends to decrease.

As a preferable range of the composition of the oil lubricant, it is necessary to consider the time for which the oil lubricant contacts with the high-temperature mold and the molten metal, the pressure at the time of production, the glossy surface of the product to be processed, and whether or not there is a solution for preventing sedimentation of the powder in the oil lubricant. It is preferable that the amount of the inorganic powder is suppressed to 1% by mass to 5% by mass in the high-pressure casting in which the contact time with the high-temperature mold and the molten metal is short and the oil- The amount of the inorganic powder can be set to a high concentration in the gravity and low pressure casting, which is common in that the contact time with the high-temperature mold and the molten metal is long and the oily lubricant is stirred. In this case, the inorganic powder is preferably 5% by mass to 15% by mass. In the forging in which ultrahigh pressure is applied, it is preferable that the inorganic powder is 3% by mass to 7% by mass in consideration of damage to the product.

When the powdery oil-based lubricant of the present invention is used for gravity casting or low-pressure casting, it is preferable to use an oil-based lubricant of 80 to 90 mass%, a solubilizer of 0.8 to 4 mass%, an inorganic powder of 5 to 15 mass% By mass to 1% by mass. If the amount of the inorganic powder is less than 5 mass%, the effect of preventing sticking becomes less. On the other hand, when the amount of the inorganic powder is more than 15 mass%, the cast product tends to be scratched.

When the powdery oil-based lubricant of the present invention is used for high-pressure casting, it is preferable to use an oil-based lubricant in an amount of 85 to 97% by mass, a solubilizing agent in an amount of 0.8 to 8% by mass, an inorganic powder in an amount of 1 to 5% 2% by mass. If the amount of the inorganic powder is less than 1% by mass, the effect of preventing sticking of the particles tends to decrease. If the amount of the inorganic powder exceeds 5% by mass, the powder in the oil-based lubricant tends to precipitate or scratches may occur in the cast product.

In the case of using the powdery oil-based lubricant of the present invention for forging, it is preferable to use a lubricant containing 83 to 95% by mass of an oily lubricant, 0.8 to 8% by mass of a solubilizing agent, 3 to 7% by mass of an inorganic powder and 0.2 to 2% % By mass. If the amount of the inorganic powder is less than 3 mass%, the effect of preventing sticking becomes less. If the inorganic powder is more than 7 mass%, there is a tendency to cause a problem of scratches on the processed product.

The powder-containing oily lubricant of the present invention can suitably use a dispersing agent for efficiently dispersing the inorganic powder or a lubricating additive for imparting lubricity, if necessary.

Next, the second invention and the third invention will be described in more detail. The second invention is an electrostatic coating method for electrostatically applying a powder-containing lubricant (first invention) described above to a metal mold. It is preferable to use the electrostatic application method by the electrostatic application device (the third invention) described below. The powder-containing oily lubricant according to the first invention is liable to generate the electrostatic effect by the electrostatic coating device according to the third invention. Therefore, a so-called wraparound effect can form a homogeneous and sufficient coating film on a hidden portion, a concavo-convex portion, or a narrow portion of the mold. Further, as apparent from the examples described later, since the coated film formed on the mold surface contains the powder and can withstand high-temperature and high-load conditions, the lubricity greatly increases. Particularly, when an electrostatic application gun is provided on a multiaxial robot capable of controlling the movement of electrons, the effect of imparting an electric charge in a necessary mold area is amplified.

An electrostatic application device according to a third aspect of the present invention is a device for implementing the electrostatic application method of the second invention, and is characterized by including an electrostatic application device and an electrostatic application gun on a multi-axis robot. Fig. 1 (A) is a schematic explanatory view of an entire electrostatic coating apparatus, Fig. 1 (B) shows a situation in which a part of the apparatus is enlarged and a powdery lubricant is applied while being mounted on a robot Fig. The basic structure of the electrostatic coating apparatus of the present invention is common even when used for any purpose of high-pressure casting, gravity / low-pressure casting, and forging.

Specifically, Fig. 1 (A) and Fig. 1 (B) show an electrostatic coating device. As shown in Fig. 1 (A), the electrostatic coating apparatus mainly comprises an electrostatic coating gun 1 having a spray nozzle in which a corona discharge electrode (not shown) applying a high voltage of 60 KV or more to the tip of the gun is disposed in the vicinity, An electrostatic controller 2 electrically connected to the electrodes of the electrostatic coating gun 1, In addition, the electrostatic application device comprises a liquid pressure feeding device 4 (consisting of a tank, a gear pump, a valve, etc.) for supplying a powder-containing lubricant to the electrostatic application gun 1 and an electrostatic application gun 1 An air compressor 6 for supplying compressed air through the piping 5 to the electric power supply controller 2 and a power source 7 (AC 200 V or 100 V) for driving the electrostatic controller 2. The electrostatic controller 2 and the transformer 3 constitute an electrostatic attraction device 8. [ The electrostatic spray gun 1 has a plurality of pneumatically actuated fluid control valves (not shown) relating to the discharge control of the air spray and the powdery lubricant containing lubricant. The electrostatic spray gun 1 is connected to the air control system 13 by an air tube. The transducer 3 controlled by the electrostatic controller 2 may be incorporated in the electrostatic coating gun 1. In this case, The high voltage from the transformer 3 is transmitted to the electrode of the electrostatic coating gun 1. [ The powder-containing oily lubricant is supplied to the electrostatic coating gun 1 by the liquid pressure conveying device 4 and is atomized by air spray from the spray nozzle mounted on the electrostatic coating gun 1. [ When electric power is outputted from the power source 7, the electrostatic charge applying device 8 acts. Compressed air for pneumatic actuation is supplied from the air control system 13 to the electrostatic spray gun 1. [ Further, the built-in fluid control valve is opened to start air spraying. When the electric power from the power source 7 is stopped, the electrostatic applying device 8 is stopped, the fluid control valve is closed, and the air spray is stopped. It is designed so that the timing of spraying and the timing for imparting a power interruption are linked. The atomized lubricant containing powder is atomized and applied to the mold in a charged state by the high voltage corona discharge phenomenon in the corona discharge electrode disposed in the vicinity of the spray nozzle. In addition, the distance between the molds of the high-pressure casting and forging apparatuses is short, and it is necessary to downsize the electrostatic coating gun 1. [ One of the features of the present invention is that the gun main body is miniaturized by separating the transformer 3 from the outside without incorporating the transformer 3 in the electrostatic coating gun 1. [ In addition, since the electrostatic coating gun 1 is small, it is lightweight, and the operation of the robot at the time of mounting the robot is improved.

In the embodiment described later, EAB90 type manufactured by Asahi Sunac Co., Ltd. is used as the electrostatic coating gun 1. [ As the electrostatic controller 2, a BPS1600 model manufactured by Asahi Shunaku Co., Ltd. was used. As the liquid pressure feeding device 4, a K-pump (0.5 cm 3) type manufactured by Landesburg and a type BHI62ST-18 manufactured by Oriental Motor were used in combination.

As shown in Fig. 1 (B), the multi-axis robot 9 is provided in a casting machine (not shown). The electrostatic application gun 1 is attached to the multi-axis robot 9 through a bracket 10. The residue 11 negatively charged from the electrostatic coating gun 1 and atomized is sprayed onto the grounded metal mold 12 as shown in Fig. 1 (B).

As described above, the electrostatic coating apparatus includes an electrostatic applying device 8 including an electrostatic controller 2, a transformer 3, and a power source 7, and an electrostatic coating gun 1 provided on the multi-axis robot 9 . With this configuration, since the electrostatic field is formed so as to surround the metal mold 12, the negative charges 11 charged with negative polarity are applied so as to follow the electrostatic field. Therefore, it is possible to apply the powdery, oily lubricant to the portion of the mold (for example, the back surface of the mold) where the electrostatic coating gun 1 is not directly facing.

Example

Hereinafter, the powdery oil-based lubricant for processing non-ferrous metals according to Examples and Comparative Examples of the present invention will be described in detail. Further, the present invention is not limited to the following embodiments, but may be embodied by modifying the constituent elements without departing from the gist of the invention. Further, various inventions can be formed by appropriate combination of a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, the constituent elements may be appropriately combined so as to be another embodiment.

(A) Production method

First, one-tenth of the predetermined amount of the solvent, which is the main component of the oily lubricant, is put into a heatable stainless steel cauldron equipped with a stirrer. Next, the predetermined amount of the powder (galactite) having dispersibility is put in, and the mixture is gently stirred for 5 minutes. Thereafter, all the powder having no dispersibility is added and stirred for 10 minutes. Further, a predetermined amount of the solvent is added and stirred for 10 minutes. Subsequently, a predetermined amount of the lubricant additive and the remaining solvent are added, and the mixture is heated to 40 DEG C while stirring, and then stirred for 10 minutes. Separately, a predetermined amount of water and a solubilization agent are preliminarily mixed, and the mixture is stirred for 10 minutes while being heated to 40 占 폚. Finally, confirm that there is no sediment.

(B) Composition of sample

The samples used in the examples have the following composition.

OIL LUBRICANT: The basic composition of the oily lubricant for explaining the present invention is three kinds (oily lubricants A, B and C) and has a similar composition as shown in Table 1. However, depending on the test purpose, the amount of water, solubilizer and powder was changed appropriately with respect to the oily lubricant. The specific composition is described in each section.

Water: tap water having a hardness of about 30 obtained from the water is used. When there is no special substrate, 0.4 mass% of water is used.

Solubilizer: a mixture of alcohol-based nonionic ion, sorbitan monooleate and alkylbenzenesulfonic acid metal salt (calcium salt) from Takemoto Yushi Co., Ltd. (trade name: New Calgen 140). When there is no special substrate, 1.6 mass% is used.

Powder mixture: 1 part of a clay (manufactured by Clay Products Co., Ltd.) having excellent dispersibility with surface treatment and organic matter added, 1 part of talc manufactured by Nippon Talc K.K., and 1 part of calcium carbonate produced by Sankyo Seiyun K.K. Were mixed in appropriate amounts according to the purpose.

However, in Table 1,

* 1 Solvent: trade name of Shell Chemical Co., Ltd. Shellzol TM: flash point 90 ° C

* 2 High Viscosity Mineral Oil: Product name: Bright Stock: Viscosity: 32 mm / s (100 ° C)

* 3 Silicone oil 1: Asahi Kasei Walker Product name of release agent,

* 4 Silicone oil 2: AKA-10000 (high molecular weight), trade name of Asahi Kasei Walker Co.,

* 5 Vegetable oil: Trade name of Meito Yushi Kogyo Co., Ltd.:

* 6 Lubricant additive 1: Organic molybdenum, trade name: ADEKA brand name: Sakura Lube 165

* 7 Lubricant Additive 2: Sulfide ester, manufactured by Gozakura Co., Ltd. Product name: GS-230

* 8 Lubricant additive 3: Ca soap, product name of Infinium: M7101

* 9 Dispersant: Acrylic copolymer: Product name of EFKA-3778 from Wilberliss Co., Ltd.

(C) Measurement method

(C-1) Measurement method of electrical resistance

And is measured by an electrostatic tester (Model EM-III) manufactured by Asahi Shunaku Co., Ltd. in accordance with ASTM D5682. A sample (lubricant) of about 50 cm 3 is sampled in a 100 cm 3 beaker and the electrical resistance is measured. Further, since the indicator of the electric resistance value is unstable in the region where the measured value is high, the average value of the five measurements is used as the measured value.

(C-2) Method of measuring adhesion amount

(C-2-1) Attachment testing machine

Fig. 2 shows a coating apparatus for measuring an adhesion amount. The power and temperature regulator 22 is installed on the stage 21 of the adhesion testing machine. The iron plate mount 24 incorporating the heater 23 is provided on the base 21 in the vicinity of the power and temperature controller 22. The steel plate supporting metal fitting 25 is provided on one side of the iron plate mount 24 and the test piece is disposed on the inside of the steel plate supporting metal fitting 25. The thermocouples 27a and 27b are connected to the heater 23 and the iron plate support metal fitting 25, respectively.

(C-2-2) Measurement method of adhesion amount

1. Preparation of Test Specimens

An iron plate 26 (square with a side length of 100 mm, thickness of 1 mm) serving as a test piece is baked in an oven at 200 캜 for 30 minutes. Thereafter, after cooling overnight with a desiccator, the mass of the iron plate is measured up to 0.1 mg unit.

2. Application of lubricant

First, the power and temperature controller 22 of the coating apparatus (manufactured by Yamaguchi Kiken Co., Ltd.) shown in Fig. 2 is set at a predetermined temperature, and the iron plate supporting metal fitting 25 is heated by the heater 23. Here, when the thermocouple 27a reaches the set temperature, the iron plate 26 as the test piece is placed on the iron plate support metal fitting 25, and the thermocouple 27b is brought into close contact with the iron plate 26. Thereafter, when the temperature of the steel plate 26 reaches a predetermined temperature, an amount of the lubricant 28 is applied to the steel plate 26 from the electrostatic application gun. Thereafter, the iron plate 26 is taken out, and is vertically kept for a predetermined period of time in the air to cool the iron plate 26, and the oil falling from the iron plate 26 is squeezed out. The coating conditions were an iron plate temperature of 250 ° C, a coating amount of 0.3 cm 3 / s, and a distance between the iron plate and the tip of the nozzle was 200 mm.

3. Measurement of adhesion amount

The iron plate 26 with the adhered material is put in an oven at 105 DEG C for 30 minutes, and then taken out. Thereafter, it is air-cooled and cools with a desiccator for a certain time. Thereafter, the mass of the iron plate 26 to which the adhered substance is attached is measured up to 0.1 mg unit, and the adhered amount is calculated from the mass change of the test piece before and after the test.

(C-3) Method of measuring frictional force

The frictional force is measured using a friction tester shown in Fig. 3, which has a good correlation with the actual equipment of the high-pressure casting. When the measured value is 98 N or less, there is no problem in actual production even when the cast product is taken out. Above that, partly sticking occurs. In addition, in case of sticking in this tester, production stoppage due to sticking also occurs in actual equipment. 3 (A) and 3 (B) are diagrams showing the method for measuring the frictional force of the test piece in the order of the process. The method of using the friction test by the friction tester of FIG. 3 is as follows. A steel plate 31 (SKD-61 product, 200 mm x 200 mm x 34 mm) of an automatic tensile tester (product name: Lub Tester U) manufactured by Mac International Inc. And a thermocouple 32 is incorporated therein. The iron plate 31 for friction measurement is heated by a commercially available heater. When the instruction of the thermocouple reaches a predetermined temperature, the frictional measuring steel plate 31 is vertically erected. The lubricant 28 is applied from the application nozzle 33 under the same conditions as the adhesion test. Immediately, the friction measuring steel plate 31 is placed horizontally on the testing machine table 34 as shown in FIG. 3 (B), that is, with the coated surface of the friction measuring steel plate 31 facing upward. Further, an abrasive product maker's manufacturing ring 35 (product of S45C, inner diameter 75 mm, outer diameter 100 mm, height 50 mm) is placed on the center of the friction measuring steel plate 31. Subsequently, 90 cm 3 of the molten aluminum 36 (ADC-12, temperature 670 ° C) dissolved in the melting furnace for ceramics is poured into the ring 35. Thereafter, it is cooled for 40 seconds to solidify. The iron weight 37 of 8.8 kg was slowly placed on the immediately solidified aluminum (ADC-12), and the friction force was measured by the built-in deformation system while the ring 35 was being pulled in the direction of the arrow X do.

(C-4) Method of measuring temperature of leiden frost

The steel plate used for the adhesion test is placed in a commercially available electric air passage and heated. Next, the surface temperature of the steel plate is measured by a non-contact type thermometer. Subsequently, when the surface temperature reaches 400 캜, drop the droplet of the lubricant from the pipette (about 0.1 cm 3). Then, the state of the droplet immediately after the drop is observed, and the following 1) to 3) are performed.

1) If the droplet is rolling or moving, raise the surface temperature by 10 ° C and repeat the test.

2) If droplet splashes, lower the temperature by 10 ℃ and repeat the test.

3) Finds the boiling temperature under relatively low motion conditions between 1) and 2) above. This temperature is referred to as a Leiden frost temperature.

(C-5) Heat transfer rate measurement

A metal test piece (10 mm, thickness 2 mm) in the form of a button cell was placed at the center of a test piece (square having a side length of 100 mm) of the adhesion tester and a magnet was placed on the back surface of the test piece, Respectively. In order to attach the coating film to the metal test piece, the application test of the adhesion test was carried out. The coating conditions were 250 deg. C, the coating amount 0.3 cm3 / s, and the coating distance 200 mm. As the lubricant, a mixture of 9% by mass of the powder in the oily lubricant B shown in Table 1 was used, and the film thickness was adjusted by changing the application frequency. Thereafter, a thermocouple for temperature measurement was welded to the back surface of the metal test piece. This metal test piece was set on a heat transfer rate measuring instrument (type TC-7000) of Laser-Flash method manufactured by ULVACO Corporation. The specific heat and the thermal diffusivity were measured, and the heat transfer rate was calculated from the value and the previously measured density of the test piece. The measurement was carried out three times for each sample, and the average value was used as a measurement value.

(C-6) Tang flow measurement

(C-6-1) Tang flow tester

Figs. 5 to 10 are views of a flow rate tester for molten aluminum used in an embodiment of the present invention, which is made of iron. Fig. 5 is a schematic view after assembling each part of the bath flow testing machine. Fig. 6 is a side view of the stand 51 of the bath flow tester, Fig. 7 (A) is a side view of the cover of the bath flow tester, and Fig. 7 (B) Fig. As shown in Fig. 5, the bath flowability tester is composed of an iron pad 51, an iron lid 52 disposed on the pad 51, and a measurer 53, a rod 54, a gas burner 55, and a handle 56. As shown in Fig. 6, the pedestal 51 has a protrusion 51a projecting upward in one end along the longitudinal direction, and a slope 51b is formed in the protrusion 51a. As shown in Fig. 7 (A), the lid 52 is formed with an inclined surface 52a as a portion contacting the inclined surface 51b when the lid 52 is disposed on the stand 51. As shown in Fig. An inclined surface 52a of the lid 52 is provided with an inlet port 52b for discharging the molten metal and a groove 52c (20) communicating with the inlet port 52b and through which the molten aluminum flows, as shown in Fig. 7 (B) Mm width, 2.5 mm height). 8A is a view of a measure 53 of isolyte for introducing molten aluminum and includes an opening 57 for letting the molten aluminum flow into the measure 53 and a lid 52 A 10 mm hole 58 communicating with the inlet port 52c of the lid 52 is formed on the bottom. 8 (B) is a stopper for temporarily collecting the molten aluminum, and is a rod 54 of isolyte.

(C-6-2) Tang flow test method

The operation of the flow resistance test of Fig. 5 is as follows. First, the iron stand 51 and the lid 52 are separately placed on the gas burner 55 and heated to a predetermined temperature (350 DEG C). Further, the meter 53 and the rod 54 are heated to about 500 DEG C with a separate burner. The lubricant is applied to the groove 52c of the lid 52 and the lid 52 is placed on the pedestal 51 by holding the lid 56 of the lid 52. When the lid 51 and the lid 52 reach the predetermined temperature, Leave. The metering 53 is placed on the lid 52 so that the inlet 52b of the lid 52 is communicated with the hole 58 of the metering 53 and the hole 54 is closed with the rod 54. [ Separately, 90 cm 3 of an aluminum molten metal (AC 4 CH 3 material, temperature 700 ° C.) dissolved in a melting furnace for ceramics is sampled with a metal scoop and immediately poured into the scale 53. After 5 seconds, rod 54 is removed from hole 58 and molten metal is spilled. After 30 seconds, the lid 52 is removed, and the length of aluminum solidified on the stand 51 is measured. The longer the length of aluminum flow, the better the flow of the water.

(C-7) Measurement of film thickness

(C-7-1) Measurement of film thickness -1: Non-contact type

Using an infrared optical microscope (Model VK-9500) manufactured by Gensen Kabushiki Kaisha, the film thickness of a coating film composed mainly of a powder on an iron plate is measured. It is basically the same operation as a microscope. In the case of measuring the film thickness of the coating film, a tape containing heat-resistant glass fibers is adhered to the center of the adhesion test steel plate 26 (see (C-2-2)), and the powder-containing lubricant is applied to the steel plate 26 . When the film thickness is measured, when the tape is slowly peeled off, a step is formed between the coating film and the test piece metal. This step is measured to obtain a film thickness. The measurement range is from 1 탆 to 500 탆.

(C-7-2) Measurement of film thickness -2: Contact type

An electronic film thickness measuring instrument (LE-300J type) manufactured by Ketkagakuken Kouskyo Co., Ltd. is used, and the measurement range is 5 占 퐉 to 500 占 퐉. Since it is of a contact type, there is a possibility that the accurate film thickness can not be measured by the pressure at the time of measurement, and a measurement value calibrated by a non-contact type optical microscope is used. On the other hand, since the advantage is the movable type, it is possible to measure the film thickness even with a large test piece which can not be put on a microscope [such as a test piece obtained by a flow rate test of (C-6)).

(C-8) Formability evaluation test

(C-8-1) Moldability evaluation tester

Figs. 9 to 13 are moldability evaluation tester simulating the mold of gravity casting used in the embodiment of the present invention. In addition to the flowability of the test evaluated by the tang flow tester of Fig. 5, The influent can be evaluated. Fig. 9 is a schematic view of a mold for use in the moldability evaluation tester and the moldability evaluation test. The moldability evaluation tester is made of iron, and the left mold 61 and the right mold 65 are assembled and used. Fig. 10 is a detailed view showing an upper surface and an inside of the left mold 61, Fig. 11 is a detailed view showing an upper surface and an inside of the right mold 65, and Fig. Fig. 8 is a view for explaining the operation of the evaluation test of the performance.

10, the left mold 61 is provided with a semicircular notch 62a for forming a sprue 62 for introducing molten aluminum, and a notch 62a communicating with the notch 62a And a cavity portion 63 of a product shape are formed. The cavity portion 63 is formed into a rib shape branched three by three on the right and left sides, and is made up of 18 cells 64 in total. The numbers in the cells 64 indicate the thickness of each cell, and the thicknesses of the cells 64 are different. For example, the thicknesses of the cells 64a, 64b, and 64c are 10 mm, 8 mm, and 6 mm, respectively, while the thicknesses of the cells 64d, 64e, and 64f are 6 mm, 4 mm, and 2 mm, respectively. As shown in Fig. 11, a notch portion 62b having a semicircular shape is formed in the right mold 65, and as shown in Fig. 9, the notch portion 62a of the left mold and the furnace By combining the teeth 62b, the sprue 62 is formed.

(C-8-2) Evaluation method

The operation of the moldability evaluation test is as follows. First, as shown in Fig. 12, the left mold 61 and the right mold 65 are heated to respective temperatures determined by the respective gas burners 66. Then, as shown in Fig. Next, a lubricant is applied to the left mold 61 and the right mold 65, and after a few seconds, the left mold 61 and the right mold 65 are combined as shown in Fig. Immediately, the aluminum molten metal 68 (AC4CH 700 ° C) is poured from the melting furnace into the iron scoop 67 and the molten aluminum 68 (about 2.8 kg) is poured from the sprue 62. After the aluminum solidification (about 2 minutes), the left mold 61 and the right mold 65 are divided and the cast product 69 solidified in the left mold 61 (FIG. 13 (A), FIG. 13 ). Finally, each cell is observed to determine the number of cells in which the aluminum is completely filled with the cavity. When the number of the completely-formed portions 70 is large, it is judged that the moldability is good and the flowability is good. On the other hand, if the number of incompletely shaped portions 70 is large as in the regions 70 ₄ and 70 _{8 in} FIG. 13 (B), it is determined that the flowability is poor.

(C-9) Temperature measurement

A contact type thermometer (HFT-40 type) manufactured by Anritsu Keiki Co., Ltd. The measurement range is 200 to 1000 占 폚. Especially, it was used to measure the surface temperature of the bath flow tester and the friction tester.

(C-10) Ring compression test

(C-10-1) Ring compression tester

14 is a view for explaining an outline of a ring compression tester. The ring compression tester can measure the coefficient of friction between the solid aluminum and the lubricant when the solidified aluminum specimen is deformed under high load. The ring compression tester includes a lower die set 81 and an upper die set 82. The die 83 is placed on the lower die set 81 and the aluminum test piece 85 is placed on the die 83 with the lubricant 84 interposed therebetween. The punch 86 is disposed on the lower surface of the upper die set 82 and the lubricant 84 is applied on the lower surface of the punch 86.

(C-10-2) Ring compression test method

This test method for evaluating friction under a high load is in accordance with the ring compression test described in the literature of the Cold Forging Sub-Committee, Warm Forging Study Group, Japan Society of Plasticity and Machining (Plasticity and Processing Vol-18, No. 202, 1977-11) . The outline of the test is that the lubricant 84 is applied to the lower surface of the punch 86 fixed to the upper die set 82. A lubricant 84 is applied to the die 83 fixed to the lower die set 81 and an aluminum test piece 85 is placed thereon. Thereafter, pressure is applied in the direction of the arrow A to deform the aluminum test piece 85. The coefficient of friction was read from the inner diameter reduction ratio of the deformed aluminum test piece 85.

(C-11) Evaluation of forged actual equipment

15 is an explanatory diagram of a situation in which an electrostatic coating apparatus is mounted on an actual forging apparatus in a tentative manner. The actual equipment shown in Fig. 15 was used to evaluate the lubricity of the lubricant at the time of forging (compression bending). The actual forging apparatus has an upper die set 91 and a lower die set 92 opposed to each other and an upper die 93 and a lower die 94 respectively disposed inside these die sets. Cartridge heaters 95a and 95b are embedded in the upper mold 93 and the lower mold 94, respectively. The electrostatic application gun 97 (discharge mechanism) for electrostatically applying the lubricant 96 to the metal mold is disposed between the upper mold 93 and the lower mold 94 only at the time of application. The cartridge heaters 95a and 95b are electrically connected to the temperature raising unit 98 to adjust the temperature. The temperature control unit 100 is electrically connected to each of the upper mold 93 and the thermocouples 99a and 99b embedded in the lower mold 94. [ A lubricant 96 is applied to the upper mold 93 and the lower mold 94 from the electrostatic application gun 97 incorporated in the robot. Thereafter, the work is set on the lower mold 94, and the upper mold 93 is lowered to start molding. The conditions for the forging were as follows: a mold temperature of 250 占 폚, a load of 2500 KN on the work, a work temperature of 470 占 폚 to 490 占 폚, and a round rod of aluminum (about 10 cm diameter 占 50 cm) as the workpiece. The size of the finished work is about 50 cm x 20 cm x 2 cm. The strain is obtained from the change in the position of the upper die set before and after forging.

(C-12) Method of measuring viscosity

The absolute viscosity (cP) at 40 ° C measured by a rotational viscometer according to JIS-K-7117-1 and the kinematic viscosity at 40 ° C from the specific gravity were calculated.

(C-1) Method of measuring flash point

The flash point of the sample was measured by the Pensky-Martens method according to JIS-K-2265.

(D) components and test measurement results

(D-1) Mixing enabling electrostatic application

As described above, the electric resistance value of the oily lubricant is infinite and is unsuitable for electrostatic application. It is known that the electric resistance value is lowered by dissolving water in an oily lubricant. However, it is difficult to dissolve water in an oily lubricant mainly composed of petroleum hydrocarbons, and in the absence of the solubilizing agent, the water precipitates.

(D-1-1) Electric resistance by mixing water and solubilizing agent

Therefore, the mixing ratio of the optimum water and the solubilizing agent in the case of mixing a predetermined amount (10 mass%) of the above-mentioned powder mixture into the oil-based lubricant A was confirmed by measuring the electric resistance value by the measurement method described in (C-1) .

As shown in Table 2, when the moisture content of Comparative Example 1 and Example 1 was 0 mass%, the electric resistance value was infinite. On the other hand, as shown in Examples 2 to 5 and Comparative Examples 2 to 4, when water is solubilized, the electric resistance value in the tester is lowered. If the electric resistance value is high, it is necessary to apply the high voltage to the actual device. If the electric resistance value is too low, the possibility of electric leakage in the actual device is high. From the viewpoint of performance and safety, it is said that the electric resistance value of about 5 to 400 M? Is preferable in the paint industry. However, the electric resistance value is a value measured at a voltage of 1.5 V. Since there is no correlation with a high voltage of an actual device of 60 KV, this range is considered to be a standard. Lubricants containing a polarized lubricant additive have experience in practical applications, even in a wider range of electrical resistance values. On the other hand, although it is difficult to find because the powder is dispersed, when the water content exceeds 8 mass% and the solubilizing agent exceeds 30 mass%, considerable turbidity is seen. From these points, it can be seen that water is 7.5% by mass or less, and the solubilizing agent is in a preferable range of 0.3% by mass to 30% by mass.

However, in Table 2,

* 1 Oil-based lubricant A: Use the same as Table 1

* 2 Water, Solubilizer, and Powder Mixture: Use the same composition as "(B) Sample composition"

(D-1-2) Electrical resistance by powder mixing

(D-1-1) described the mixing ratio of the optimum water and the solubilizing agent in the case of mixing a predetermined amount of the powder in the oily lubricant. In the following Examples 6 to 9 and Comparative Example 5, when water and a solubilizing agent were made constant (0.2 mass% of water, 0.8 mass% of a solubilizing agent) and the amount of the powder mixture was changed as shown in Table 3 The electrical resistance values are summarized. The electric resistance value was measured by the measuring method described in (C-1). As shown in Table 3, when the powders were mixed as in Examples 6 to 9 as compared with Comparative Example 5, the electric resistance value by the 1.5 V testing machine was increased. However, as described later, electrostatic application of the powder-containing oil-based lubricant at 60 KV was possible.

However, in Table 3,

* 1 Oil-based lubricant A: Use the same as Table 1

* 2 Powder mixture, water, solubilizer: Use the same composition as "(B) Sample composition"

(D-2) Influence on adhesion and friction by powder mixing

By mixing the powder with the oil lubricant, it is possible to suppress the boiling of the lubricant in the hot metal mold and to improve the wettability of the lubricant to the metal mold. As a result, the adhesion amount increases, and the effect of "friction reduction / sticking prevention" can be expected. In addition, since the inorganic powder is not deteriorated or decomposed at high temperatures, it is prevented from sticking at high temperature, and the use temperature range of the lubricant is increased. In addition, the coating film becomes a heat insulating material, Flow "can be expected.

(D-2-1) Influence on LF temperature

Table 4 shows the results of examining the temperature of LF (Leidenfrost) by the test method described in (C-4) for Comparative Examples 6 to 13 in order to investigate the relationship between the degree of dolbidity of the lubricant and the amount of the powder. The LF temperature was measured under the condition that electrostatic application was not performed using a sample in which a powder mixture was mixed with the oily lubricant A Each of the samples of Comparative Examples 6 to 13 was adjusted by the composition shown in Table 4 so that the water and the solubilizing agent were constant (0.4 mass% of water, 1.6 mass% of solubilizing agent).

In Table 4, however,

* 1 Oil-based lubricant A: Use the same as Table 1

* 2 Powder mixture, water, solubilizer: Use the same composition as "(B) Sample composition"

* 3 Soluble release agent: A-201 product of Aoki Kagaku Kenku Sho is diluted 40 times.

Comparative Example 7 (powder = 0.1 mass%: LF = 450 deg. C) and Comparative Example 8 (powder = 0.3 mass%: LF = 460 (Powder = 5 mass%: LF = 510 deg. C), Comparative Example 9 (powder = 1 mass%: LF = 460 deg. The LF temperature was increased. That is, it can be seen that increasing the powder mixing amount increases the boiling temperature and improves the wetting of the lubricant to the mold. However, as in Comparative Example 12 (powder = 10 mass%: LF = 510 deg. C) in which the fine powder was mixed and Comparative Example 13 (powder = 15 mass%: LF = 510 deg. 510 ° C. From the above, it was confirmed that the LF temperature rises by mixing the powder in the oil lubricant. For this effect, it is necessary to mix at least 0.1 mass% of the powder, but the increase of the LF temperature reaches the limit by the powder mixing of about 5 mass%.

(D-2-2) Effect on adhesion

If the LF temperature is increased by mixing the powders, an increase in the amount of deposition can be expected. In order to confirm this, an adhesion test was carried out by applying the coating composition from the electrostatic application apparatus shown in Fig. 1 by the test method described in (C-2) (hereafter, in all cases of electrostatic application, Is applied using an electrostatic application device). The test conditions were an iron plate temperature of 250 캜, an application pressure of 0.05 MPa / cm 2, a fluid pressure of 0.005 MPa / cm 2, a coating distance of 200 mm, and a coating amount of 0.3 cm 3. However, in the case of Comparative Example 14, since the electrostatic coating gun was not used, the air pressure was 0.4 MPa / cm 2. Each of the samples of Examples 10 to 15 and Comparative Examples 14 to 18 was further mixed with the oil-based lubricant A in such a manner that the powder mixture shown in Table 5 was appropriately mixed with the sample mixed with 0.4 mass% of water and 1.6 mass% of the solubilizing agent, And the total amount is adjusted to be 100% by mass.

However, in Table 5:

* 1 In the case of Comparative Example 14, an ordinary spray gun (manufactured by Yamaguchi Kiken K.K.) was used instead of the electrostatic coating gun.

* 2 A powder mixture was mixed with 0.4 parts by mass of water and 1.6 parts by mass of a solubilizing agent to the oily lubricant A (the same composition as in "(B) sample composition") was used.

* 3 Use the same water-soluble mold release agent as in Table 4. The water-soluble release agent is pressed at about 275 ° C

From the results in Table 5, the following can be seen.

1. Comparison with water-soluble release agent

The amount of water soluble release agent that accounts for 90% of the market is 2.5 ㎎. On the other hand, the adhesion amount of the oily lubricant (all comparative examples and examples) is 5.0 mg to 49.9 mg, which is 2 to 20 times higher than that of the water-soluble release agent, and the adhesion temperature is as high as about 80 ° C to 150 ° C. The reason is that as shown in Table 4, the LF temperature is higher than 200 占 폚.

2. Adhesion effect by electrostatic application gun (no electrostatic discharge)

Comparative Example 15 (electrostatic application, no electrostatic charge, no powder: 20.4 mg) showed an adhered amount of 15.4 mg compared to Comparative Example 14 (ordinary non-electrostatic application, no electrostatic charge, no powder: . Even when there is no electrostatic charge, the electrostatic coating gun itself is excellent from the viewpoints of the diameter of the coated particles and the application pressure, and the adhesion is greatly increased.

3. Adhesion effect by electrostatic charge when powder is not mixed

The adhesion amount of Comparative Example 16 (using electrostatic application gun, powder-free, electrostatic applied 60 KV: 25.1 mg) was 4.7 mg more than Comparative Example 15 (using electrostatic coating gun, powder-free, electrostatic application 0 KV: adhesion amount 20.4 mg) , And the adhesion efficiency was improved by 23%. This is a result of efficiently attaching the lubricant mist charged with the electrostatic application gun to the metal plate.

4. Adhesion effect by powder mixing when no static electricity is applied

As can be seen from the comparison between Comparative Example 15 (powder zero: deposition amount: 20.4 mg) and Comparative Example 18 (3 mass% of powder: 31.3 mg) in the case of not applying to the electrostatic application gun, the deposition amount by powder mixing was 10.9 (53% increase in adhesion) were observed. As can be seen from the observation of the LF temperature described above, when the powder is mixed, the LF temperature rises and the dolbid is suppressed. That is, since the dolby ratio of the oily lubricant on the vertical plane of the hot test piece is suppressed, the amount of the oily lubricant splashed from the surface of the test piece is lowered. As a result, the wettability to the test piece is improved, the adhesion efficiency is increased, and the adhesion amount to the test piece is increased.

5. Combination effect of powder mixing and electrostatic charging

Comparative Example 17 (powder = 0.1% by mass: adhesion amount = 25.4 mg) and Example 10 (powder = 0.3% by mass: As shown in Example 14 (powder = 3 mass%: deposition amount = 34.7 mg) and Example 14 (powder = 10 mass%: deposition amount = 49.9 mg) Almost linearly.

Through the mixing of powders and electrostatic application, the amount of adhesion increased significantly. As a result, it is possible to expect an effect of preventing sticking and a lubricant application amount reduction effect. In addition, it is expected that the use range is expanded to a high temperature by forming a coating film on the mold surface.

(D-3) Effect of Solvent Powder in Lubricant on Electrostatic Coating

As shown in Table 1, the compositions of the evaluation samples so far used a solvent having a flash point of about 90 ° C as a main component. In the absence of powder mixing and electrostatic attraction, a solvent was used in expectation of fast drying (quick-drying) in order to increase the amount of adhesion on the mold surface. That is, the applied lubricant mist rapidly dried on the mold surface, and the deterioration of the frictional force caused by the decrease in the thickness of the oil film due to the falling to the lower side of the mold surface was controlled.

On the other hand, mixing of powders and electrostatic application have the effect of increasing the deposition amount, thickening the coating film, and reducing the frictional force. Therefore, in the present invention in which powder mixing and electrostatic application are performed, quick drying property may not always be required. In order to confirm this point, in Comparative Example 19 and Comparative Example 20, the frictional force of a lubricant containing a base oil (mineral oil) as a main component for a lubricating oil having a higher flash point (less quick-drying property) than a solvent was evaluated . The frictional force was evaluated according to the test method described in (C-3). The application conditions were as follows: a coating amount of 0.3 cm 3, an air pressure of 0.05 MPa / cm 2, a coating distance of 200 mm, and an electric charge of 60 KV. The sample was obtained by changing the solvent in the sample to base oil based on Comparative Example 16 (electrostatically coated type, powder-free). The physical properties, composition and friction test results of Comparative Examples 14, 16, 19 and 20 are shown in Table 6.

However, in Table 6:

* 1 Comparative Examples 14 and 16: Using the same materials as those listed in Table 5

* 2 Base oil 1: Synthetic lubricant base oil (PAO-8) of Group 4 of the American Petroleum Association, NEXBASE 2008 (flash point 240 ° C) sold by Showa San-

* 3 Base oil 2: Refining base oil of Group 1 of the American Petroleum Institute, N-500 (flash point 230 ° C) sold by Japan Energy Co.,

* 4 Ingredients other than base oil 1 and base oil 2: Use the same composition as in "(B) Sample composition" and Table 1

* 5 Non-incendive coating is the same as the normal case described in Table 5

As described above, the determination in the friction tester is 98 N, and if it is less than 98 N, it is determined that there is no partial pressing, and if it exceeds, partial pressing and sticking occurs and it is judged to be just before the pressing. Comparative Example 16 (the solvent is the main component) in Table 6 is 147 N at 350 占 폚, and the press-bonding is already occurring at a part, and is just before the adhesion. In the case of Comparative Example 19 (the synthetic base oil being the main component), 137.2 N, which is not different from Comparative Example 16, was obtained. In the case of Comparative Example 20 (the main component of the refined base oil), the adhesion at 350 ° C occurred. However, from the experience of the present applicants, there is no significant difference in the results of the friction forces of " 137.2 N and 147 N " and " In the case of Comparative Example 16 and Comparative Example 19, it is presumed that sticking occurs at 355 ° C. On the other hand, from the results of Comparative Example 14 (normal gun) and Comparative Example 15 (electrostatic spray gun, electrostatic spray gun) in which the same oily lubricant shown in Table 5 was evaluated, the deposition amount was about four times as much as that of using the electrostatic spray gun. From these points, it is considered that the electrostatic coating can be utilized to thicken the coating film or widen the application area.

Therefore, a substance whose performance deteriorates by incorporating a base oil at a high flash point instead of a solvent can be sufficiently covered by applying an electric charge. The present invention is effective even in the case of using a high-flash point oily lubricant.

(D-4) Evaluation for high-pressure casting

(D-4-1) Adhesion · Frictional force test: Right angle injection

As described above, it is possible to expect the effect of preventing the adhesion of the press with the increase of the adhesion amount. Table 5 shows the results of the evaluation using a friction tester having a good correlation with an actual apparatus, using the test method described in (C-3). The coating conditions on the test piece are the same as the adhesion test, and they are injected at right angles to the test piece. From the results in Table 5, the following becomes clear.

1. Adhesion effect by static electricity

Comparative Example 15 (electrostatic application) and Comparative Example 16 (electrostatic application = 60 KV) were all in a state immediately before being stuck at 147 DEG C at 350 DEG C, and adherence occurred at 375 DEG C. In addition, both of Comparative Example 18 (powder = 3% by mass, no electrostatic charge) and Example 12 (powder = 3% by mass, electrostatic charge at 60 KV) all had the same frictional force and did not adhere to 425 占 폚. For the same powder amount, the pressing temperature was the same. That is, the effect of applying the electrostatic charge to the frictional force was not found. However, as will be described later, when the coating is applied parallel to a metal mold having irregularities instead of perpendicular to the metal plate, the effect of reducing the frictional force due to the application of the electrostatic force is remarkable. Also in the gravity casting, the effect of reducing the frictional force by applying the electrostatic force is remarkable.

2. Adhesion effect by powder mixing when no static charge is applied

Comparative Example 18 (powder = 3% by mass) exhibited a low friction of 58.8 N to 78.4 N up to 425 캜, as compared with Comparative Example 15 (powder = 0% by mass: pressed at 375 캜). It is obvious that the mixing of the powder contributes to the reduction of the frictional force. It is presumed that the powder which is not deteriorated even at a high temperature reduces the direct contact between the iron plate and the solidified aluminum to prevent the adhesion.

3. Combination effect of powder mixing and electrostatic charge

The friction force was slightly reduced in Example 11 (powder = 1 mass%: 78.4 N at 350 占 폚) as compared with Comparative Example 16 (powder = 0 mass%: 147 N at 350 占 폚). Example 14 (powder = 10 mass%: 68.6 N at 425 캜) and Example 15 (powder = 15 mass%: 68.6 N at 425 캜) in Example 12 (powder = 3 mass% N), the frictional force was reduced and the withstand temperature increased by 50 DEG C as the amount of powder mixture was increased. However, if the content of the powder is 3 mass% or more, the effect of reducing the frictional force is not increased.

(D-4-2) Adhesion · Frictional force test: parallel injection

The mold has parallel sides or hidden sides as seen from the application direction. Particularly, a core pin or extruding pin, which is a portion where pressing and sticking is likely to occur, is a cylindrical shape, so that there is also a back surface on which a coated particle is hardly adhered. The electrostatic application can promote adhesion of the oily lubricant to such areas.

In Example 16, as shown in Fig. 4, an oil-based lubricant was applied to the test piece 42 from the electrostatic coating gun 41 in parallel, and the amount of adhesion and the frictional force were measured. The mounting condition of the test piece 42 was centered at an offset position spaced by 200 mm from the tip of the electrostatic coating gun 41 on the center line in the direction of applying the lubricant and 60 mm away from the center line. The center of the applied test piece 42 was placed at this offset position and the application surface of the test piece 42 was arranged so as to be parallel to the application direction. Test piece for measurement of adhesion amount and test piece for frictional force measurement were all arranged in the same manner. The coating conditions were the same as in the case of the above-mentioned right angle injection (Example 12), and the coating amount was 0.3 cm 3 and the air pressure was 0.05 MPa / cm 2. In addition, as Comparative Example 21, the adhesion amount and the frictional force were measured in the same manner as in Example 16 except that no electrostatic charge was applied. The measurement results of Examples 12 and 16 and Comparative Example 21 are shown in Table 7. The evaluation samples of Examples 12 and 16 and Comparative Example 21 were obtained by mixing 0.4% by mass of water, 1.6% by mass of a solubilizing agent and 3% by mass of a powder mixture in the oil-based lubricant A.

In Table 7, however,

* 1 A mixture of 3 mass% of a powder mixture based on 0.4 mass% of water and 1.6 mass% of a solubilizing agent was mixed with the oil-based lubricant A (the same composition as in "(B) sample composition") was used.

As shown in Table 7, in the case of Comparative Example 21 in which the electrostatic application was not performed while using the electrostatic application gun, the adhesion amount in the range of 250 占 폚 to 350 占 폚 was almost zero at 0.1 mg. Therefore, in the friction test at 350 占 폚, the pressing adhesion occurred. On the other hand, in the case of Example 16 in which electrostatic force was applied, the adhesion amount was 4.5 mg at 250 캜, and the frictional force at 350 캜 was a sufficiently low level of 68.6 N. There was no difference in comparison with the frictional force level at 350 DEG C of the perpendicularly sprayed Example 12. Obviously, the electrostatically charged electrostatically charged charged mists were attracted to the steel specimen, resulting in a so-called wraparound phenomenon. From this result, even when an actual metal mold has many concavities and convexities which are not contacted with the lubricant mist at a right angle by applying electrostatic coating, a coating film can be formed and the occurrence of sticking can be reduced. In addition, as described above, in the case of a water-soluble releasing agent which accounts for 90% of the market, even if sprayed at a right angle, the amount of adhesion is only about 2.5 mg. The deposition amount of Example 16 in which parallel spraying was performed at the time of electrostatic application was 4.5 mg, and the present invention is excellent.

(D-4-3) Evaluation of actual machine by high-pressure casting machine

In the adhesion test and the friction test at the right angle injection, the effects of the mixing of the powder and the electrostatic charge application showed an increase in the adhesion amount, an increase in the coating film, and an expansion in the range of the temperature to prevent the adhesion. Further, in the adhesion test and the friction test at the time of parallel jetting, a wraparound phenomenon of a mist of the lubricant due to the electrostatic application was observed. That is, excellent effects of electrostatic application of the powder-containing lubricant as the first invention were confirmed experimentally. Therefore, in order to confirm the adhesive property and the pressing property in an actual high-pressure casting machine, the casting apparatus owned by the applicants was evaluated. The evaluation conditions were a casting machine of 2500 ton mold, a maximum temperature of the mold immediately after application, about 350 ° C, a coating amount of 9 cm 3, and a coating speed of 20 seconds. The composition and evaluation results of the samples are shown in Table 8 (Example 12, Comparative Examples 15-1, 15-2 and 18). The adhesion was visually evaluated, and the white powder was applied to the mold using a spray can (developer of dye-penetrant tester, manufactured by Takeshi Kasei Co., Ltd.) to whiten the entire surface. Thereafter, an oily lubricant was applied, and the white powder on the mold surface was wetted with the oily lubricant and changed to a blackish appearance. It was judged that the lubricant was adhered to the blackened portion and the lubricant was not adhered to the white portion. In addition, it was judged whether or not the pressing sound could be cast in actual production.

In Table 8, however,

* 1 A powder mixture was mixed with 0.4 parts by mass of water and 1.6 parts by mass of a solubilizing agent in the oil-based lubricant A (the same composition as in "(B) sample composition") was used.

* 2 Using the normal gun described in * 1 in Table 5

As shown in Table 8, in the case where no electrostatic charge was applied in Comparative Example 15-1 (powder-free) and Comparative Example 18 (powder included), the area where the lubricant was applied was about 1-2% of the surface of the mold , And the case of using the electrostatic coating gun was a little better. That is, the effect containing the powder was hardly seen. On the other hand, when electrostatic charge was applied in Comparative Example 15-2 (containing no powder) and Example 12 (containing powder), the entire surface of the mold was wet. That is, the presence or absence of the powder does not affect the wettability of the lubricant, and the application of static electricity greatly affects the improvement of the wettability. This is considered to be the result of the fact that the metal mold surface has many concavities and convexities and the wraparound effect due to the application of the electrostatic force is exhibited. In the case of Comparative Example 15-1 (normal operation), continuous casting could not be carried out, and production was stopped in several cases. In the case of Comparative Example 15-2 and Example 12 in which the entire surface was wet, continuous casting was possible and 40 pieces were produced and evaluation was stopped. Compared with Comparative Example 15-2, the superiority of the powder of Example 12 was not found in this evaluation, but Example 12 using at least a powder-containing oily lubricant did not show the deposition of powder on the mold. That is, it can be predicted that the lack of the thickness of the cast product due to the deposition of the powder does not occur, and it can be judged that the problem does not occur in the actual equipment. As shown in Table 5, in the laboratory adhesion test, remarkable increase in the adhesion was observed due to the effect of the combination of applying the electrostatic charge and mixing the powder. In this respect, in the case of Example 12 in an actual device, it is estimated that the application amount can be reduced as compared with Comparative Example 15-2.

(D-5) Gravity and low pressure casting

Compared with high-pressure casting, the pressure to press aluminum melt is designed to be low in gravity and low-pressure casting. Therefore, the speed of the molten aluminum is slow, so that the molten aluminum melts, the viscosity of the molten aluminum increases, and the molten aluminum sometimes solidifies on the way. As a result, the problem that the molten aluminum does not flow into every corner of the mold easily occurs. As shown in Table 5, it was found that the deposition amount can be significantly increased by the inclusion of the powder and the electrostatic application. As the deposition amount increases, the coating film in the mold becomes thicker and heat transfer from the molten aluminum to the mold can be expected to be lowered. As a result, the temperature drop of the molten aluminum is reduced, and the molten aluminum flows downward, and it is expected that the molten aluminum flows into all the corners of the mold.

In the case of the oily lubricant A used in Table 5, since there are many high viscous oil components, in the gravity casting which is in contact for a long time, carbonization occurs on the cast product, and coloring problems are likely to occur. To solve this problem, water, a solubilizing agent, and a powder were mixed based on an oil-based lubricant B (low oil content) having a high viscosity oil fraction. Thus, a test was also conducted to confirm that the amount of the powdered material and the amount of deposition by electrostatic application increase in the oil-based lubricant B, and the adhesion is decreased.

(D-5-1) Adhesion in Low-Oily Mixture, Powder Mixing for Friction, Effect of Power Outage

The lubricant was adjusted to the composition shown in Table 9. The coating conditions were an electrostatic coating gun, a coating amount of 0.3 cm 3, a coating distance of 200 mm, and a coating air pressure of 0.05 MPa / cm 2. For the adhesion test, the test method described in (C-2), and for the friction test, the method described in (C-3) was used.

In Table 9, however,

* 1 Oily lubricant B: Use the same one as shown in Table 1

* 2 Water, Solubilizer, Powder Mixture: Use the same composition as the above "(B) Sample composition"

As shown in Table 9, all of Comparative Example 22 (powder = 0% by mass, no electrostatic charge) and Comparative Example 23 (powder = 0% by mass, electrostatic charge) all stuck at 375 ° C. In Comparative Example 24 (powder = 10% by mass, no electrostatic charge was applied), there was no sticking at 375 ° C, but it was stuck at 400 ° C. On the other hand, in Example 17 (powder = 10% by mass, with electrostatic charge), no adherence was observed up to 425 占 폚. Therefore, even in the case of an oily lubricant which slightly reduces high viscosity oil, the effect of the mixing and electrostatic application of the powder of the present invention is shown (as shown in Table 1, the oily component of the oily lubricant A is 11 mass% and the oily component of the oily lubricant B is 3.5 Mass%, and the deposition amount is 49.9 mg to 46.5 mg, respectively, under the conditions of the powder content of 10 mass% and the electrostatic charge application condition).

(D-5-2) Effect of Powder on Heat Transfer

As described above, the amount of the lubricant adhered to the mold increases according to the present invention. Thus, the heat transfer coefficient of the coated film was measured by the method described in (C-5). The coating film thickness was adjusted by changing the number of application times once, six times, and twelve times. In addition to the heat transfer rate measurement, samples for thickness measurement were also prepared by the same operation. The heat transfer rate is the average value measured three times for the same sample, and the average value is summarized in Table 10. The film thickness was measured with a contact type / film thickness meter. However, the measured values of the contact type and film thickness measuring device were calibrated in advance using a non-contact type film thickness measuring device, and the calibrated values are shown in Table 10. Each sample of Example 18 and Comparative Example 25 in Table 10 was adjusted by the composition shown in Table 10 so that the water and the solubilizing agent were constant (0.4 mass% of water, 1.6 mass% of solubilizing agent).

However, in Table 10:

* 1 Oily lubricant B: Use the same one as shown in Table 1

* 2 Water, solubilizer, powder mixture: Use the same composition as "(B) Sample composition"

* 3 Measurement of heat transfer rate without using lubricant

The coating film of Example 18 (containing powder) was thicker than that of Comparative Example 25 (not containing powder) in Table 10 (one application). Further, when the number of times of application of the powder of Example 18 was increased, the coating film became thicker in proportion to the number of times of application by 18.2 占 퐉 (once coating), 103 占 퐉 (6 times coating) and 216 占 퐉 (12 times coating). In addition, the heat transfer coefficient of the film decreased from 0.773 W / cmK (film thickness of 7 mu m) to 0.295 W / cmK (film thickness of 216 mu m) in Comparative Example 25 corresponding to the film thickness. It has become apparent that the heat transfer from the molten aluminum to the mold is lowered by thickening the coating film. As a result, the temperature drop of the molten aluminum contained in the mold is reduced, the temperature of the molten metal is kept high, the viscosity of the molten aluminum is not increased, and the molten metal flow distance is expected to be long.

(D-5-3) Influence of Powder on Bath Flow Distance

As described above, it is possible to expect that the molten metal flow distance of the molten aluminum becomes longer due to the reduction of the heat transfer coefficient. This was confirmed by the test method described in (C-6) using the flow tester of FIG. 5. Table 11 shows the composition, coating conditions and test results of the samples.

However, in Table 11,

* 1 Oily lubricant B: Use the same one as shown in Table 1

* 2 Non-cyclic spray gun use the same one as shown in Table 5

* 3 The dispersant, the powder mixture, the water and the solubilizing agent are the same as those used in "(B) sample composition"

Comparative Example 26 in Table 11 was tested under the conditions that no powder was contained and no electrostatic charge was applied, and Comparative Examples 27, 28, and 29 contained powder and were not electrostatically charged. In addition, Example 19 contained the powder and was tested under the condition of electrostatic application. Compared with Comparative Examples 26, 27, 28 and 29, when the mixing amount of the powder was increased from 0 mass% to 20 mass%, the coating film thickness increased to 10, 40, 71, and 138 占 퐉, respectively. On the other hand, the water flow distances were increased to 5 ㎝, 28 ㎝, 37 ㎝, and 50 ㎝, respectively.

In the current situation of water-soluble graphite in actual equipment, the initial film thickness is 100 탆 to 150 탆. The water flowability in the laboratory tester using this water-soluble molding agent is about 35 cm. Taking this into consideration, it is sufficient that Comparative Example 28 in which the powdery oil-based lubricant is not electrostatically coated (37 cm in hot flow). In the case of Comparative Example 29, since the powder content was a high concentration of 20% by mass, the flow rate was evaluated under the condition of applying the electrostatic charge at 10% by mass. In Example 19 with the same application amount, the film thickness increased from 71 탆 to 111 탆 and the water flow distance increased from 37 cm to 50 cm as compared with the 100 cm 3 coating of Comparative Example 28 (maximum length of the tester was 50 cm Comparative Example 29 and Example 19 can be said to be " 50 cm or more ", but measurements are too good to be measurable).

Obviously, when the powder is contained and electrostatic application is performed, it can be said that the flowability of the water is improved. Estimation based on the coating film thickness, and in the case of Example 19, when the application amount is 50 cm 3 to 60 cm 3, the water flowability of about 35 cm of the water-soluble patterning agent of the prior art can be ensured. There is an advantage that the application amount can be made about half by electrostatic application. As a result, by suppressing the thickness of the excessive coating film, the cooling ability after the molten metal flows can be improved, and the cycle time required for one product can be shortened. That is, there is an advantage of excellent working efficiency. In the case of a water-soluble patterning agent, since water is scattered, it is consumed for drying the mold almost all day. On the other hand, in the case of using a powder-containing oily lubricant and electrostatic application, the drying time is several seconds, and the working efficiency is remarkably extended.

(D-5-4) Practical evaluation of gravity casting equivalent to actual equipment

As described above, when electrostatic application of the powder-containing oily lubricant is carried out, the heat transfer rate of the applied coating film is lowered, and the flow distance of the bath becomes longer. This laboratory test result was evaluated by the method described in (C-8), using a moldability evaluation tester (large-sized tester at a mold weight of about 500 kg) of FIG. 9 close to the actual apparatus. The molten metal temperature was 680 占 폚 and the mold temperature was 200 占 폚 to 250 占 폚. The composition, coating conditions and test results of the samples are summarized in Table 12.

However, in Table 12,

* 1 0.4% by mass of water, 1.6% by mass of a solubilizing agent and a powder mixture are mixed with an oil-based lubricant B (the same as in Table 1), and adjusted to 100% by mass in total with the powder mixture. The water, the solubilizing agent, and the powder mixture are the same as those used in "(B) sample composition"

* 2 Normal nozzle: Use the same one as shown in Table 5

The rating of Comparative Example 30 (no powder, no static charge) was 3/18 (only three out of 18 were molten). In the case of Comparative Example 31 (containing powder, no electrostatic charge), the rating is still 8/18, which is still bad. In the case of Comparative Example 32 (without electrostatic charge) in which the powder was increased and the application amount was increased, it was significantly improved to 17/18. On the other hand, in Example 20 (using an oil-based lubricant containing a powder and electrostatic application), the evaluation was 18/18, and good performance was confirmed. In addition, the surface of the cast product was clean when containing powder. It is considered that voids are formed between the coating film and the cast product due to the inclusion of the powder and that the generation of pores caused by the escape of gas generated from the oil in the coating film from the voids appears on the surface of the cast product.

In addition, the "wraparound phenomenon of static electricity" shown in the laboratory test was investigated as a molding evaluation device corresponding to the actual equipment. In the case of Comparative Example 33 in which no electrostatic charge was applied, when it was applied in parallel, the rating was as low as 7/18. On the other hand, in the case of Example 21 in which electrostatic charge was applied, the rating was improved to 11/18. The wrap-around phenomenon of electrostatic discharge was confirmed in a large-scale testing machine.

(D-6) Forging

(D-6-1) Ring compression test

The surface pressure of the friction tester described in (C-3) was 0.023 MPa, and superiority of the powdery lubricant was confirmed under these conditions. However, it is difficult to apply this superiority to the film strength of the forging which is processed under high load conditions of 10000 to 100000 times. Therefore, in order to evaluate under a high load, the friction coefficient was evaluated using the ring compression tester (1290 MPa, surface pressure of about 60,000 times of the friction tester) shown in Fig. As the test method, the method described in (C-10) is used. The test conditions were as follows: compressibility of 60 ± 2%, ring inner diameter of 30 mm, punch temperature of 175 ± 20 ℃, work temperature of 450 ℃, application amount of 1.32 ㎖ (20 cm3 / min, 0.33 cm3 / sec × 2 sec, Lt; / RTI > Table 13 shows the average value of the sample composition, coating conditions, and friction coefficient measured three times.

However, in Table 13

* 1 Oil-based lubricant C (same as in Table 1) was mixed with 0.8 mass% of water, 3.2 mass% of solubilizing agent and a powder mixture, and the total amount was adjusted to 100 mass%. The water, the solubilizing agent, and the powder mixture are the same as those used in "(B) sample composition"

Comparative Example 34 is a case where no lubricant is used, and the coefficient of friction is as high as 0.58. On the other hand, Comparative Examples 35 and 22 are cases in which a powdery, oil-based lubricant is applied. The friction coefficient of Comparative Example 35 in which electrostatic application is not performed is 0.327, whereas the friction coefficient in Example 22 in which electrostatic application is performed is 0.290. Obviously, the effect of reducing the frictional force due to the electrostatic attraction was shown. The superiority of the present invention was confirmed even under a high load condition.

(6-2) Evaluation of forged actual equipment

Since the effect of the present invention can be confirmed by a laboratory test (ring test) under a high load as described above, the effect on the actual apparatus for forging shown in Fig. 15 was also examined. The evaluation conditions were a maximum sliding distance of 50 mm at the time of compression bending, a mold temperature of 250 ° C, a load target value of 2500 KN, a work temperature of 470 ° C to 490 ° C, and a material of A6061 alloy. However, the target load value was 2500 KN, but the measured value was 2670 KN. The coating conditions were an injection amount of 0.5 cm 3 / second and a coating time of 3 seconds, and the coating amount was 6 cm 3 in total because the coating was applied to the upper mold and the lower mold. Table 14 shows the composition of the sample, the application conditions, and the strain of the measured product.

However, in Table 14

* 1 Comparative Example 37 and Example 23: The same composition as in Comparative Example 35 and Example 22 in Table 13. 0.8% by mass of water, 3.2% by mass of a solubilizing agent and a powder mixture were mixed with the oil lubricant C (same as in Table 1), and the total amount was adjusted to 100% by mass. The water, the solubilizing agent, and the powder mixture are the same as those used in "(B) sample composition"

* 2 Comparative Example 36 was prepared by diluting a water-soluble lubricant: WF: white lube (trade name, manufactured by Daihei Kagaku Kogyo K.K., water glass system) in 10 times of water

The strain of Comparative Example 37 (powder-containing oil-based lubricant without electrostatic charge) was 70.9%, and the strain of Example 23 (powder-containing oil-based lubricant, electrostatic force) was 72.4%. The effect of electrostatic application was shown and agreed with the prediction from ring compression tester.

However, the strain of Comparative Example 36 (commercially available water-soluble lubricant) was 72.7%, which is equivalent to that of Example 23. From the viewpoint of the strain, the merits of the working process can be expected. As shown in Table 4, the LF temperature of the casting water-soluble releasing agent is about 240 ° C, and the water-soluble lubricant for forging of Comparative Example 36 having almost the same water content is also estimated at 240 ° C. On the other hand, the LF temperature of the oily lubricant is 510 ° C. That is, in the case of the water-soluble lubricant for forging, the mold temperature is set at about 180 ° C. in order to secure the adhesion amount in the field. When the mold temperature is raised, the adhesion amount of the lubricant drops, and the coating film becomes thinner. In the case of the oily lubricant, the coating amount does not decrease even if the mold temperature is raised by 100 DEG C or more, so that the coating film is not thinned. Therefore, the amount of heat taken away from the work can be reduced. If the hot forging can be performed at a higher temperature, there is an experience that the strain becomes higher. In addition, in the case of a water-soluble lubricant for forging, which is a multi-step process, there is a work re-warming-up step in order to compensate for the decrease in temperature. If the mold temperature is raised from about 250 占 폚 to 350 占 폚 by 100 占 폚, the work re-warming-up step becomes unnecessary, and the production process can be shortened and the investment can be reduced. Further, in the case of the oily lubricant having a coating amount of less than 1/10, the cooling is hardly caused, and the re-win-on process is surely omitted. In addition, by increasing the mold temperature, the work becomes flexible and the molding load can be reduced. Therefore, the present invention is advantageous in terms of the working process.

(D-7) Summary of measurement results

From the above-described test results, the following has become clear.

1) Combination to enable electrostatic application

By mixing "0 mass% to 7.5 mass% of water and 0.3 mass% to 30 mass% of a solubilizing agent" to prepare a powder-containing oily lubricant, electrostatic application became possible. With respect to the electric resistance value, the electric resistance acts in the infinite direction by containing the powder, and when the water is mixed, the electric resistance acts in a direction to lower the electric resistance. The solubilizer also serves to dissolve water in oily lubricants. As will be described later, even when the electric resistance value when applied at 1.5 V is high, when the applied voltage is 60 KV in an actual device, the adhesion amount increases. It is presumed that the presence of the polar lubricant additive in the oil lubricant enables electrostatic application.

2) Influence on adhesion by powder mixing

The LF temperature of 0% by mass of the powder was 510 ° C by mixing 440 ° C and 5% by mass of the powder. By mixing the powders, the LF temperature of the oily lubricant was increased. It slowly boils from the protruding portion of the powder by boiling the lubricating component little by little, thereby suppressing the dolbid. This is the same effect as the prevention of the dolbid caused by the zeolite in the chemical experiment. However, the effect is up to 5% by mass of the powder, and even if the powder is mixed, the effect tends not to occur.

Under the condition that no electrostatic charge was applied, the deposition amount was increased only by mixing the powder. When 3 mass% of powders were mixed with an oil - based lubricant, the adhesion amount in the adhesion tester increased from 20.4 ㎎ to 31.3 ㎎. This is a result of the fact that the Dolby ratio is suppressed on the vertical mold surface by the rise of the LF temperature by 60 占 폚. That is, it is presumed that the wettability of the oil-based lubricant to the mold surface is improved, and the mist of the oil-based lubricant splashing from the mold surface is reduced and the adhesion is increased.

By applying the electrostatic charge, the adhesion amount was further increased. And 34.7 mg and 49.9 mg respectively in powder mixtures of 3% by mass and 10% by mass. It is much higher adhesion than 2.5 mg of water-soluble mold release agent which accounts for 90% of the market, compared with 5 mg of oily lubricant which does not use powder and is not electrostatically coated. It can be said that it is the empirical data according to the composition of the first invention.

The adhesion improvement effect of the electrostatic application gun itself was also observed. Under the condition that no powder was contained and no electrostatic charge was applied, the deposition amount of the oil-based lubricant in the " normal gun " was 5.0 mg, whereas the " electrostatic coating gun " The electrostatic coating gun itself is devised, and the adhesion efficiency is very high, and it forms a part of the effect according to the apparatus of the third invention.

In addition, with respect to the composition of the oily lubricant of the first invention, it has become clear that it is not necessary to mix the solvent. Under the condition that the electrostatic application is not performed, it is necessary to impart quick drying property to the oil film adhered to the metal mold, and to form a dry film on the metal mold quickly. That is, mixing efficiency with the solvent is increased. However, since the adhesion efficiency can be supplemented by the electrostatic application, the quick drying property is not necessarily required, and the solvent may not be mixed. In fact, replacing solvents with highly viscous refined base oils and synthetic base oils exhibited electrostatic adhesion equivalent to that of solvents. A lubricant base oil (mineral oil) of the fourth petroleum (the flash point of 200 ° C or higher) may be used in the present invention.

3) Influence on the friction by the inclusion of powder

The inclusion of the powder in the lubricating grease reduced the pressing of the mold. The frictional force at 350 占 폚 under the condition of performing the electrostatic application was lowered to 156.4 N at 156.8 N (immediately before the adhesion) when the powder was not contained and 78.4 N at 1% by mass powder mixture. Further, by containing 3 mass% of the powder, the powder did not adhere at 425 占 폚. Compared to about 250 ° C in the case of using a water-soluble release agent and 350 ° C in the case of an oily lubricant containing no powder, the present invention does not cause sticking to much higher temperatures, and its application range is wide. It can cover almost 100% of the operating temperature range of the high-pressure high-speed casting machine on the market.

However, only the effect by the electrostatic application showed little effect in the case of the right angle injection in the case of containing the powder. It is presumed that the effect of the electrostatic coating was not observed due to the fact that by adding the powder, Therefore, the "wraparound effect" of the blackout by the parallel jet was examined, and a remarkable blackout effect was observed. In the case where the oil lubricant of 3 mass% of the powder was sprayed parallel to the test piece, the friction force was 68.6 N when the electrostatic application was not performed, and when the electrostatic application was carried out at 350 deg. The deposition amount at that time of 250 DEG C was increased to 4.5 mg in the case of electrostatic application, compared with 0.1 mg in the case of no electrostatic application. The effect on this tester was confirmed by the moldability evaluator close to the actual equipment. The effectiveness of the composition of the first invention and the application method of the second invention was confirmed.

4) Influence on insulation by powder mixing

The heat transfer coefficient of the coating film was remarkably lowered. The coating film had a thickness of 216 탆 and a thickness of 0.285 W / cmK for 0.773 W / cmK in the case of no coating film. It is impossible to expect a significant decrease in heat transfer coefficient due to the thickness of several micrometers in high pressure casting and several micrometers to ten micrometers in thickness even forging. However, in the gravity and low pressure casting, a film having a thickness of about 100 占 퐉 to 150 占 퐉 is formed, Is effective.

In the hot flow test for gravity and low pressure casting, the hot flow distance was remarkably increased due to the decrease of the heat transfer rate. No flow of static electricity was observed, and the flow of the water which was 5 cm at the coating film 10 m was 37 cm at the coating film 71 m. In this case also, the effect of the electrostatic application is shown. In the case where the electrostatic application is not performed under the same application conditions, the flow of the water which was 37 cm at the coating film thickness of 71 탆 is 50 ㎝ or more.

5) Adhesion in low-temperature oil blending, mixing of powders for friction, electrostatic effect

As a review for gravity and low-pressure casting, which is mainly applied in large quantities, a "color mark" is generated in a product after casting. This is a problem in which a large amount of high-viscosity hydrocarbons is carbonized. Therefore, the blend with reduced oil content was examined. Even when the oil content was reduced from the oil-based lubricant A having an oil content of 11% by mass to the oil-based lubricant B of 3.5% by mass, the adhesion amount of the 10% by mass powder was equivalent to 49.9 mg to 46.5 mg.

6) Friction under compression

A ring test was conducted under a high load of about 60000 times that of the laboratory friction tester. As a result of comparing the friction caused by the presence or absence of the electrostatic application using the powder-containing lubricant, the frictional coefficient decreased from 0.327 in the case of no electrostatic application to 0.290 in the case of electrostatic application, The effect was confirmed.

7) Effects on actual devices

a) High pressure high speed casting

The wettability of the coating liquid on the mold surface was significantly improved by applying a static electricity. It can be said that the wraparound effect due to the electrostatic application is exhibited. On the other hand, since the whole surface of the mold was wet, the effect of mixing the powder was not clear in this evaluation. Also, even when the powders were mixed, the actual production was continued for 40 times without pressing and sticking to the actual equipment, and evaluation was stopped. It can be estimated from the laboratory test results in (D-4-1) and (D-4-2) that the amount of application can be reduced in actual equipment.

b) gravity casting

A moldability evaluation tester simulating an actual apparatus is superior in evaluation point to a case in which powder is contained and electrostatic is applied as compared with a case in which no powder is contained and no electrostatic charge is applied, there was. This is because the coating film is thickened, the heat insulating property is improved, and the flowability of the water is improved.

c) Forging

The friction reduction effect of the present invention was shown in a ring compression tester under a high load. As a result of confirming this effect using an actual device, it was found that when the strain was contained and the electrostatic application was carried out, the strain was 72.4% as compared with the strain of 70.9% when the powder was contained and the static electricity was not applied. . This was equivalent to the strain of commercially available water-soluble lubricant of 72.7%. However, in the case of the present invention, the application amount is as small as one tenth, and since the lubricant is also a lubricant, the LF temperature is high. Therefore, it is possible to set the mold temperature higher than 100 deg. C, and the rewarming step for the work can be omitted, and the working time can be expected to be greatly shortened.

8) Conclusion

1) to 7), the following excellent effects were confirmed by electrostatically applying the powdery oil-based lubricant from various evaluation results.

1. Increase of deposition amount of powder-containing oil-based lubricant on mold. Compared with the case where the powder is not contained, even if the coating amount is the same, the coated film becomes thicker and the range of the pressed up becomes narrow. In the case where there is no adhesion, it is possible to further reduce the application amount.

2. Adhesion prevention effect. The temperature at which the sticking occurs becomes 350 ° C to 425 ° C or more, and the application range of the powdery lubricant containing lubricant is remarkably increased. It is effectively used in high pressure casting, gravity casting, forging.

3. Wrap around effect. By applying the electrostatic force, the powder-containing oily lubricant can be adhered even to the hidden portion of the metal mold having a complicated shape, and the case in which the lubricant can be used is further expanded. It is effectively used in high pressure casting of complex structure.

4. Insulation effect. It is possible to increase the deposition amount of the powdery oil-based lubricant and to form a thick coating film, thereby improving the heat insulating property and improving the flowability of the water. It is effectively used in gravity casting.

5. Shortening drying time. Since it is a powdery oil-based lubricant, the drying time is shorter than that of the water-soluble lubricant, and the drying time is several seconds. It is effectively used in gravity casting.

6. Adhesion at high temperature. It is possible to reduce the re-warm-up process in forging by increasing the mold temperature. It is effectively used in forging.

The method for electrostatically applying the powder-containing lubricant of the present invention is suitable for casting and forging the non-ferrous metal.

1: electrostatic application Gun 2: electrostatic controller
3: Transformer 4: liquid pressure feeding device
5: Piping 6: Air Compressor
7: Power supply 8:
9: Multi-axis robot 10: Bracket
11: Remains (oil droplets) 12: Mold
13: Air control system 21:
22: power supply and temperature controller 23: heater
24: iron plate bracket 25: iron plate supporting bracket
26: iron plate 27: thermocouple
28: Lubricant 31: Friction measuring steel plate
32: thermocouple 33: dispensing nozzle
34: tester 35: ring
36: Molten aluminum 37: Iron churn
41: electrostatic application gun 42: test piece
51: large 51a: protrusion
51b: slope 52: cover
52a: inclined surface 52b: inlet
52c: groove 53: measure
54: rod 55: gas burner
56: handle 57: opening
58: hole 61: left mold
62: Sprue 62a:
62b: notch portion 63: cavity portion
64: Cell 65: Right mold
66: Gas burner 67: Scoop
68: Molten aluminum 69: Foundry products
70: region 81: lower die set
82: upper die set 83: die
84: Lubricant 85: Aluminum test piece
86: punch 91: upper die set
92: lower die set 93: upper die
94: lower mold 95: cartridge heater
96: Lubricant 97: Electrostatic spray gun
98: heating unit 99: thermocouple
100: Temperature control unit

Claims (5)

delete 1. A powdery oil-based lubricant for a metal mold comprising 60 to 98.7 mass% of an oil lubricant, 0.8 to 30 mass% of a solubilizer, 0.3 to 15 mass% of an inorganic powder, and 0.2 to 7.5 mass%
Wherein the powder-containing oily lubricant is capable of having electric charge. A method for electrostatic application comprising electrostatically applying the powder-containing lubricant according to claim 2 to a metal mold. delete 3. The lubricant composition according to claim 2, wherein the powdery, oily lubricant is used in an electrostatic application device,
Wherein the electrostatic application device electrostatically applies the powder-containing oily lubricant to a mold,
Wherein the electrostatic application device comprises an electrostatic application device for applying static electricity to the powdered lubricant containing lubricant and an electrostatic application gun disposed on the multi-axis robot.

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